It was delicious. I took a picture of the curd spread on bread, but don't let that fool you. I mostly have been eating this stuff with a spoon out of the jar.
I would double the recipe if you have enough limes. Since I only had two, I made a very small batch. Considering the spoon situation I mentioned above, this is probably for the best.
1 egg
1 egg yolk
2/3C sugar
1/4C lime juice (this was a little short using just the lime juice, so I topped it off with bottled lemon juice I had in the fridge)
Zest of both limes
2tbs butter, in pieces
In a metal bowl, whisk together the eggs, sugar, juice, and zest. Place the bowl over a pot of boiling water to create a double boiler. You could do this straight on the stove top, but then you risk adding too much heat at once and scrambling your eggs. You want to just slowly bring them up to heat, stirring continuously. If they start to scramble, immediately pull the mixture off the heat and continue to stir.
After 5-10 minutes, the curd should be thickened, and pull away from the edge of the bowl. At this point, lower the heat even more, and stir in the butter, one little piece at a time, melting it slowly into the curd.
Then lick every appliance you used to create the curd. Pack a jar or a tupperware, or use immediately. This stuff is so versatile. You can use it as a layer between cakes, you can fill linzertorte-style cookies, you can swirl into cheesecake, you can spread on bread, you can stir into oatmeal, you can top ice cream, you can fill cupcakes, you can spread onto shortbread, you can bake into a glorious lemon tart, or you can eat it with a spoon.