The above ingredient list is for lemon curd. To make lime curd simply replace the lemon zest with lime zest, and the lemon juice with a mixture of lime and lemon juice. I used two limes and one lemon for the 1/2 cup juice I needed to make my lime curd.

In a small saucepan combine the yolks, zest, juice, and sugar. Stir over medium heat until the sugar dissolves and the mixture thickens, about 8-10 minutes. Remove from heat and stir in the salt and butter (cubed). Once the butter has completely melted into the mixture allow to cool to room temperature. Strain through a fine mesh strainer, cover, and refrigerate overnight. Don't worry if your curd is still very thin; it will thicken up as it refrigerates. Use any leftover curd within a week (store covered in the refrigerator when it's not being used).

Cream together the butter and sugar. Unlike a pie crust, you don't want your butter super cold, as you want it to incorporate well with the sugar. Stir in the egg yolks. Then stir in half the flour. Now add the salt and heavy cream. Finally, stir in the remaining flour. Once a dough ball forms, use your clean hands to incorporate any remaining ingredients into the dough ball. Cover in plastic wrap and chill in the freezer for 30 minutes or in the refrigerator for a couple of hours (or overnight).

Divide the chilled dough into six pieces. Roll out the dough on a lightly floured surface until it forms a big enough circle to cover the entire tart pan. Lightly spray the tart pan with cooking spray. Lay the rolled out dough into the pan, gently pressing it into the edges. Use your rolling pin to remove any excess dough around the edges (like in the photo above). Use a fork to poke a few holes in the bottom crust. Repeat for the remaining tart pans.

Bake at 350°F for 13-14 minutes until the edges begin to brown. Allow the tart crusts to cool completely before use.

In a metal or glass bowl combine the ingredients. Set the bowl over a pot of simmering water. Do not allow the bowl to touch the water. Whisk the mixture as it cooks, about three minutes. Rub a little of the mixture between your fingers; it should feel smooth. If you can still feel the grains of sugar, keep whisking! Remove the bowl from the simmering water and use an electric mixer to beat the eggs on high for about five minutes. Beat until stiff, glossy peaks form.

Fill the cooled crusts with lemon or lime curd. I used both, and as you can see from my photos of the curd above, they were basically the same color no matter if they were lemon or lime. So if you make both I would recommend labeling them. Or don't, if you really like needing to taste them every time to figure out which is which. Pipe a little meringue on top of the tarts and pop them under the broiler for a minute or two (keep a close eye on them). You could also use a kitchen torch, if you have one.