Preparation:

• Preheat your oven to 350°F (175°C).
• Line baking sheets with parchment paper or silicone mats.

Making the Dough:

• In a large bowl, beat the softened butter and granulated sugar together until light and fluffy.
• Add the eggs one at a time, mixing well after each addition.
• Stir in the vanilla extract.
• In a separate bowl, whisk together the flour, baking powder, and salt.
• Gradually mix the dry ingredients into the wet ingredients until combined. The dough should be soft but manageable.

Shaping the Cookies:

• Roll out the dough on a lightly floured surface to about ¼ inch thickness.
• Use a large cookie cutter to cut out shapes and a smaller cutter to cut out shapes within the larger shapes to create windows.

Filling the Windows:

• Place the cut-out cookies on the prepared baking sheets.
• Fill the cut-out windows with crushed hard candies, using different colors for a stained glass effect.

Baking:

• Bake in the preheated oven for 10-12 minutes, or until the cookies are lightly golden and the candy has melted.
• Let the cookies cool completely on the baking sheets to allow the candy to harden.

Final Touches:

• Once cooled, dust with powdered sugar if desired.