Lemon curd is a delicious spread made from lemon juice, eggs, butter, and sugar. It has a bright, tangy lemon flavor and a lush, silky texture. Lemon curd is wonderful spread on scones, toast, or muffins, or as a tart filling. When making lemon curd at home, it can sometimes be tricky to know when it has thickened enough. Here are some tips for determining when your lemon curd is the perfect consistency.
What is lemon curd?
Lemon curd is a custard-like spread made from lemon juice, eggs, butter, and sugar. Unlike lemon pie filling or lemon pudding, lemon curd contains whole eggs rather than just yolks. This gives it a richer flavor and smoother, creamier texture. Lemon curd is tart from the lemon juice, sweet from the sugar, and decadently lush from the butter and eggs.
Lemon curd has a jam-like consistency when finished. It should be thick enough to spread but still loose and silky-smooth. The flavor is bright and refreshing, providing the perfect balance of sweet and tart. Lemon curd can be served right away but it will thicken up more as it cools in the refrigerator.
Basic ingredients
The basic ingredients for lemon curd are:
- Lemons – Freshly squeezed lemon juice provides tart flavor
- Butter – Butter gives richness and body
- Eggs – Whole eggs thicken the curd and provide richness
- Sugar – Sugar balances out the tartness
Many recipes also include cornstarch or flour to help thicken the curd. Some extra tips when choosing ingredients:
- Use fresh, juicy lemons for maximum flavor
- High quality butter provides the best results
- Choose organic or free-range eggs
- Fine granulated white sugar or caster sugar works best
How to make lemon curd
Here is a basic overview of the key steps for how to make lemon curd:
- Juice the lemons. You’ll need about 1/2 cup of strained lemon juice.
- In a double boiler or heatproof bowl set over a pot of simmering water, whisk together the eggs and sugar until fully combined.
- Gradually whisk in the lemon juice followed by the butter. Continue whisking constantly as the curd cooks.
- Cook, continuing to whisk frequently, until the curd thickens enough to coat the back of a spoon. This takes 10-15 minutes typically.
- Remove from heat and strain through a fine mesh sieve. Cool, then refrigerate until set.
The most important step is cooking the curd gently over simmering water until it reaches the right thickness. This requires paying close attention and frequent whisking.
How to tell when lemon curd is thick enough
Determining when lemon curd is properly thickened can be tricky for home cooks. Here are a few techniques to test the curd’s consistency:
Coat the back of a spoon
The classic test is to dip a spoon into the curd, then run your finger across the back of the spoon. If the curd coats the spoon and leaves a clear trail that holds its shape, it is thick enough. If it runs right back together, it needs more cooking. If it coats the spoon thickly or forms peaks, it may be overcooked.
Check the texture
Well-thickened lemon curd should have a smooth, velvety texture. It should seem thick, but still pour easily. If the texture seems thin and runny, cook it longer over low heat, whisking frequently. If it seems thick, gloppy, or stiff, it is likely overcooked.
Test the temperature
Using an instant-read thermometer takes the guesswork out of determining doneness. Lemon curd is properly thickened when it reaches 170-180°F (76-82°C). Once it hits this temperature range, immediately remove it from heat.
Allow it to cool
Lemon curd will continue to thicken and set up as it cools. Allow the finished curd to cool at room temperature for 10-15 minutes, then transfer to the fridge to chill completely before using. The cooled curd should have a jam-like spreadable consistency.
Look for these signs
Here are a few visual cues that your lemon curd is thick enough:
- It coats the back of a spoon and leaves a trail when you run your finger through it
- When dropped from a spoon, it falls off in a sheet rather than dripping off
- It holds its shape rather than running when spooned into a jar
- The whisk leaves trails and ridges when stirred through the curd
Don’t overcook it
While lemon curd needs to cook long enough to thicken, overcooking leads to problems. Signs of overcooked lemon curd include:
- Thick, gloopy, or stiff texture
- Dull or browned color
- Simmering or bubbling while cooking
- Eggy, sulfurous aroma
- Grainy or weeping whey
To avoid overcooking, use gentle heat and whisk frequently. Watch it closely near the end of cooking. Remove immediately once it’s thick enough and allow it to finish thickening during cooling.
Storing and serving
Once your lemon curd is cooked and cooled, transfer it to sterilized jars or an airtight container. Store in the fridge for up to 2 weeks. Use as a spread on scones, toast, muffins, biscuits, or croissants. Lemon curd also makes a bright, tangy filling for tarts, cakes, or thumbprint cookies. Its silky-smooth texture and bright lemon flavor brings a lovely finishing touch to all kinds of baked goods and pastries.
Troubleshooting lemon curd
Here are some common problems and how to avoid them when making lemon curd:
| Issue | Cause | Solution |
|---|---|---|
| Runny, thin curd | Undercooked | Cook longer over low heat, whisking frequently |
| Grainy texture | Overcooked or curdled | Strain through sieve; prevent curdling by tempering eggs and keeping heat low |
| Browned, dull color | Overheated | Use gentle heat like a double boiler; don’t boil |
| Eggy smell or taste | Overcooked | Remove from heat sooner; cook gently |
| Too thick | Overcooked | Cook just until thickened; allow to cool completely |
| Weepy liquid | Cooling too quickly | Let curd cool gradually before chilling; store tightly covered |
Tips for perfect lemon curd
Follow these tips for smooth, velvety lemon curd every time:
- Use fresh, juicy lemons for maximum flavor
- Cook over very gentle, even heat like a double boiler
- Whisk constantly to prevent scorching
- Remove from heat as soon as it thickens to prevent overcooking
- Strain through a sieve for the smoothest texture
- Allow to cool gradually before chilling
- Store in an airtight container in the fridge
- Enjoy within 2 weeks for the best flavor
How to use lemon curd
Once cool, lemon curd can be used in all kinds of delicious ways. Here are some serving ideas:
- Spread on scones, biscuits, toast, or English muffins
- Fillings for tarts, thumbprint cookies, crepes, or sandwich cookies
- Topping for angel food cake, pound cake, or cheesecake
- Layer in trifles or parfaits
- Stir into yogurt, oatmeal, or cottage cheese
- Dollop on fresh fruit like berries, peaches, or nectarines
- Smear inside rolled cake like a jelly roll
- Mix into buttercream frosting for cakes or cupcakes
- Smooth over croissants, brioche, or panettone
Its bright, refreshing flavor is so versatile. Get creative and enjoy lemon curd on all your favorite baked goods and desserts!
Lemon Curd Recipes
Classic Lemon Curd
Ingredients:
- 3 large eggs
- 1/2 cup fresh lemon juice (about 3 lemons)
- 2/3 cup sugar
- Pinch of salt
- 6 tablespoons unsalted butter, softened
Instructions:
- In a double boiler or heatproof bowl set over a pot of simmering water, whisk together the eggs, lemon juice, sugar, and salt until combined.
- Cook, stirring constantly with a whisk, until mixture is thickened and reaches 170-180°F on an instant-read thermometer, about 10 minutes.
- Remove from heat and slowly whisk in the butter until fully incorporated.
- Strain curd through a fine mesh sieve into a bowl or jar. Let cool to room temperature, then cover and refrigerate until chilled and set, at least 4 hours.
- Will keep refrigerated for up to 2 weeks.
Lemon Blueberry Curd
Ingredients:
- 1/2 cup fresh lemon juice
- 1/4 cup sugar
- Pinch of salt
- 3 large egg yolks
- 4 tablespoons unsalted butter, cut into pieces
- 1/2 cup fresh blueberries
Instructions:
- In double boiler, whisk together lemon juice, sugar, salt, and egg yolks.
- Cook over simmering water, stirring constantly, until thick enough to coat the back of a spoon, about 10 minutes.
- Remove from heat and stir in butter until melted and incorporated. Gently fold in blueberries.
- Strain curd through a fine mesh sieve into a bowl or jar. Let cool, then refrigerate until chilled and set, 2-3 hours.
- Store refrigerated up to 1 week.
Lemon Coconut Curd
Ingredients:
- 1/2 cup lemon juice
- 1/2 cup sugar
- 2 large eggs
- 1 large egg yolk
- 6 tablespoons unsalted butter, cut into pieces
- 2 tablespoons coconut milk
- 1/4 cup shredded coconut
Instructions:
- In double boiler, whisk together lemon juice, sugar, eggs and egg yolk until combined.
- Cook, stirring constantly, until thickened, about 10 minutes.
- Remove from heat and slowly whisk in butter until melted. Stir in coconut milk.
- Strain curd through a sieve into a bowl. Stir in shredded coconut.
- Refrigerate, covered, until set, about 4 hours. Keeps 1 week refrigerated.
Conclusion
Achieving the perfect silky-smooth texture and spreadable consistency for lemon curd takes some finesse, but a few simple techniques will help you know when it’s ready. Look for it to thicken up enough to coat a spoon, reach 170-180°F on a thermometer, and have a viscous, gloopy appearance. With the right gentle heating method and frequent whisking, you can easily make smooth, luscious lemon curd at home. Refrigerate and enjoy this bright and velvety spread on all kinds of baked goods!