About Lemon Curd

• Lemon curd is much the same as a lemon pie filling. You make it using the juice and zest of fresh lemons, sweetened with sugar, enriched with butter and thickened with egg yolks. To make it at home, whisk the sugar and yolks into the lemon juice and heat it over a double boiler until it thickens to a custard-like consistency. Beat in softened butter at the end, when you remove the curd from the double boiler. Commercial versions of lemon curd have additional stabilizers and preservatives, but are otherwise similar.

Spoon Method

• If you want to bake cupcakes with a pocket of lemon curd in the center, the spoon technique is simplest. Mix up your cupcake batter according to the recipe, and line the pan with paper cups. Spoon enough batter into each cup to fill it one-third of the way, and smooth it to a level surface. Carefully place about a teaspoon of lemon curd into the middle of each cupcake. Finally, fill each cup with additional batter. Take care to surround the lemon curd with batter, to prevent it leaking from the sides. Bake the cupcakes as usual, and allow them to cool completely before icing them.

Squeeze-Bottle Method

• The spoon method works well, but it can be time consuming. If you want to prepare a large number of lemon-filled cupcakes, or just speed the process, you might use a squeeze bottle instead. Mix the cupcake batter as usual and fill the paper cups two-thirds of the way with batter. Spoon lemon curd into a plastic squeeze bottle with a small tip. Insert the tip of the bottle into the middle of each muffin and squeeze in approximately a teaspoon of filling. Wipe the tip after filling each muffin, to minimize smearing. This technique also works after the cupcakes are baked, though you may find the filling is off-center.

After Baking

• You can also fill your cupcakes with lemon curd after they're baked. For a delicate hint of lemon, use a squeeze bottle to pipe approximately a half-teaspoon of curd into each finished cupcake. This leaves a small hole that you can easily ice over. Alternatively you can make a small well in the middle of each cupcake by scooping out a section, and then spoon lemon curd into the hollow. These are more difficult to cover with icing, but you can make it easier by saving the cut-out piece of cupcake and using part of it to cover the hole.