Preheat the oven to 375ºF.

In a mixing bowl, combine flour, baking powder, and salt.

In a separate bowl, beat 3 eggs and sugar until they thicken, about 10 minutes.

Add melted butter, water, and the flour mixture to the eggs and sugar.

Stir until the mixture becomes dough-like.

Shape the dough into a long rope about 1.

5 inches thick using your hands.

Cut it into about 20 equal pieces.

Flatten each piece of dough into a circle about 3 inches across.

Place about one teaspoonful of bean paste in the center of the circle and fold the edges of the dough toward the center.

Pinch the edges together firmly to seal.

Gently roll each cake into a ball and flatten slightly.

Repeat with the remaining dough and filling.

Use a cookie cutter to lightly press a design into the top of each cake, or draw a design with a fork tine or toothpick.

Place cakes one inch apart on an ungreased cookie sheet.

Lightly glaze the top of each cake with beaten egg.

Bake for 30 minutes or until golden brown.

Remove and allow to cool.

Serve the moon cakes at room temperature.