What you will need: Dough Recipe here Lemon Curd 3 whole eggs 3 egg yolks 1 cup granulated sugar ¾ cup fresh lemon juice 1 tbsp lemon zest 8 tbsp butter or margarine cut into pieces Swiss Meringue 5 egg whites 1 ¼ cup granulated sugar ⅛ tsp cream of tartar pinch of salt ½ tsp vanilla Directions Lemon Curd: Heat one inch of water in the bottom of a pot (make sure pot is small enough that glass bowl sits above the water and does not touch). Place the curd ingredients (except the butter/margarine) in a glass bowl and whisk together until well combined. Place the bowl over the simmering water and cook, whisking for about 8-10 minutes, until mixture has thickened and is a light yellow color. It should be thick enough to coat the back of a spoon.
Add the butter/margarine to the mixture, one piece at a time, and continue to stir until it is all incorporated. 
Strain the curd by pouring it through a fine mesh sieve into a clean bowl. The curd will continue to thicken as it cools. 
Cover with plastic wrap, with the plastic touching the surface of the curd to avoid the formation of a skin. Place it in the refrigerator until ready to use. The curd can be kept in the refrigerator for 2 weeks. Dough: Follow directions here Fill each hamantaschen with about 1 tsp lemon curd. Pinch closed to a triangle and bake about 20 minutes. 
Swiss Meringue: Combine egg whites, sugar, salt, and cream of tartar in the bowl of a stand mixer over a pot of simmering water. Whisk constantly by hand until mixture is 170° (or until warm, sugar has fully dissolved, and becoming frothy and white.)
Attach the bowl to the mixer fitted with the whisk attachment. Starting on low and gradually increasing to medium-high speed, whisk until stiff (but not dry) peaks form. Add vanilla and continue mixing until the mixture is fluffy and glossy, and completely cool, about 10 minutes. 
Fill a ziploc bag (or piping bag if you have one, or just spoon dollops of meringue) and snip the corner to pipe onto the baked hamantaschen.
Return the hamentashen to the oven set to 400° for 2-3 minutes, keeping a close eye so that the meringue doesn’t burn. If you have a kitchen torch you can do that instead. 
Enjoy!
