Preheat oven to 350°F (180°C) and line baking sheets with parchment.
Cream butter (or margarine) and powdered sugar until light and fluffy. Add vanilla extract.
In a separate bowl, whisk together flour, baking powder, and salt.
Gradually add dry mix to the butter mixture. Add water or egg replacer as needed until a soft dough forms.
Wrap and chill the dough for 30 minutes.
Roll out the dough on a floured surface to about ⅛–¼ inch thickness.
Cut out 3” circles and place 1 tsp filling in the center of each.
Pinch three sides firmly to create triangular shapes.
Place on baking sheet and bake for 12–16 minutes, or until lightly golden on edges.
Cool completely on a wire rack. Cookies will firm up as they cool.