Remove eggs from the fridge and separate them, leaving the egg whites in a bowl. Let stand at room temperature for 20-30 minutes. If you are using a pastry bag to pipe the cookies, prepare it now. Set out a baking sheet lined with parchment paper.

Preheat oven to 300 degrees.

Melt peanut butter (using a microwave or double boiler) until it is creamy. Set aside and let cool, but make sure to stir the peanut butter every few minutes, You want it to remain creamy and “runnier” than when it comes from the jar, but not be very warm.

Add egg whites to a very clean and dry bowl of an electric mixer with a pinch of salt. Begin with the mixer on low speed, and gradually increase the speed as peaks begin to form. Beat in the sugar and cream of tartar. Increase the speed to high and beat until glossy. You want stiff peaks, which took about 5-6 minutes for me.

Make sure the peanut butter is still creamy but has cooled. Add it to the egg whites and mix it through with only 4-5 folding motions (it should look like the 3rd picture down). Quickly add mixture to pastry bag or simply use a spoon and drop cookies onto the sheet. Bake for 20 minutes, then turn the oven off and let the cookies sit in the oven for 10-15 more minutes. Baking time will depend on the size of the cookies, and you need to watch them closely as they are already a golden color from the peanut butter. Remove from the oven and let cool completely. Once cool, melt chocolate (in the microwave or a double boiler) and dip half of each cookie in the chocolate. Let chocolate cool before serving.