Beat the eggs until thick, then beat in the sugar, oil and seasonings. Stir in enough flour to make a rollable dough. Roll out on a floured board until 1/4 inch thick and cut into 3 inch rounds.
Place a spoonful of desired filling in the center. Draw up three sides to form a triangle and overlap the edges together - it is better to overlap a little more than you think you need rather than have these fall open while baking. You can use a little extra orange juice on a finger tip to glue the overlap firmly if you need to. Brush the tops with a little beaten egg if you wish. Bake in a moderate oven, 350 deg. F, for ~30 min.
Each batch makes 2 dozen 3" circle hamentashen.
NB: For most fillings, jam or preserves will work, except for blueberry. Blueberry jam almost always boils and runs. Blueberry pie filling works very well, however. (Evidently it's designed to stay where you put it at high heat.)
Gluten-free substitutions:
This year, I decided to try a gluten-free version for my daughter who was diagnosed as gluten-sensitive. What I did is substitute the regular flour in the recipe with:
2 1/2 cups of Bob's Red Mill All Purpose Baking Gluten Free flour 1 1/2 cups of stone ground white rice flour
This dough cannot be rolled as thin (so won't make as many cookies), and must be refrigerated for at least an hour before rolling out. It will want to stick more than the regular dough, and yet does not hold together as well. Thus, a well floured silicone baking mat and baking on parchment paper are both very helpful for a good outcome.