Sift together all-purpose flour, baking powder, and salt in a bowl. Set aside.

Beat eggs with an electric mixer in a second bowl until smooth. Set aside.

Mix sugar, vegetable oil, orange and lemon zests and juices, and vanilla extract in a third bowl. Add to beaten eggs; mix well. Add the flour mixture and beat until the dough starts to pull away from the sides of the bowl and forms a ball.

Place dough onto a floured work surface and knead until it no longer sticks to your fingers. Shape into a disk and wrap in plastic wrap. Refrigerate for 30 minutes.

Preheat the oven to 375 degrees F (190 degrees C). Grease 2 cookie sheets.

Whisk egg, cream, and water together to make glaze.

Divide chilled dough into 4 sections. Roll out dough on floured work surface with a floured rolling pin until it is about 1/8-inch thick. Use a cookie cutter or jar lid to cut out circles about 4 inches in diameter.

Place 1 teaspoon of apricot jam in the center of a dough circle. Pinch 2 sides together to create 2 sides of a triangle. Use some of the egg glaze as 'glue' if needed. Fold the bottom of the circle up to form the third side of the 'hat,' leaving a little of the filling visible in the center. Repeat with remaining dough circles and filling.

Place cookies on the prepared cookie sheets. Brush tops with egg glaze mixture using a pastry brush. Sprinkle with sugar.

Bake in the preheated oven until light golden brown, about 18 minutes. Cool for 10 minutes before transferring to a cooling rack with a spatula.