In a large bowl with a stand or hand mixer, blend butter and sugar until light and fluffy, about 2 minutes.
Then add vanilla, 1 egg and orange juice and combine.
Then add flour, baking powder and salt and mix just until combined. Dough should be slightly sticky.
Form dough into a large ball, cover with plastic wrap and chill overnight or at least 2 hours.
When you are ready to make your hamantaschen, preheat your oven to 350 degrees F and roll out the dough on a floured surface until it is 1/8 inch thick. Use a 3 or 3 1/2-inch circle cookie cutter to cut circles in the dough. The top of a wine glass works too! Roll out the scraps and recut into circles.
Then take a teaspoon of the jam and put it in the center of each circle. Don’t add any more- the filling will spread to fill the cookie, and any more would just run over the top making for ugly yet still delicious hamantaschen.
Fold two sides together overlapping at the bottom, and then fold the top down to make a triangle.
Place on a parchment lined cookie sheet and freeze for 30 minutes to prevent spreading.
Wash with egg wash. Bake for 15 minutes or until lightly golden on the bottoms of cookies. Cool and enjoy!