Beat the eggs using a whisk attachment in an electric mixer until foamy. Gradually add the powdered sugar and whip at medium speed for 10-15 minutes until thick and resembles buttercream. In the last 5 minutes of whipping, add the baking powder and your chosen flavoring.

Slowly incorporate the cake flour while whipping at low to medium speed until fully combined into a dough, being careful not to overmix.

Wrap the dough tightly with plastic wrap ensuring it touches the surface to prevent drying. Refrigerate for several hours or overnight.

On a cornstarch-dusted surface, roll out small portions of dough to about 1/4 inch thickness. Dust the dough surface with cornstarch, press your Springerle mold firmly to imprint designs, cut around each design and transfer to a cornstarch-dusted surface to rest for 12-24 hours.

Preheat your oven to 145°C (290°F). Before baking, place each cookie on a damp paper towel for 30 seconds to moisten the bottom, then transfer to a parchment-lined baking tray.

Bake larger cookies for 18-20 minutes and medium to small cookies for 15-17 minutes. Flip and rotate the trays halfway through bake time. Cookies are done when they rise slightly with a foot and do not move when gently wiggled.

Let the cookies cool completely. Store in an airtight container at room temperature, or use dried cookies as decorative ornaments.