Prep the Oven and Pans: Preheat your oven to 350°F (177°C) and line two large baking sheets with parchment paper.
Make the Dough: In a large bowl, combine the raspberry cake mix, eggs, and melted butter. Stir with a wooden spoon or silicone spatula until a thick, cohesive dough forms. Do not overmix.
Scoop and Shape: Roll the dough into 1-inch balls (about 1 tablespoon of dough each) and place them 2 inches apart on the prepared baking sheets.
Make the Indentations: Use the back of a rounded teaspoon measuring spoon, or your thumb, to gently press an indentation into the center of each dough ball. Tip: If the dough sticks to the spoon, dip the spoon in a tiny bit of flour or cornstarch first.
Fill the Centers: Spoon about ½ teaspoon of lemon curd into each indentation. Do not overfill, or the curd will bubble over the sides during baking.
Bake: Bake for 10 to 12 minutes, or until the edges are set and the bottoms are very lightly golden. The cookies will still look quite soft, but they will firm up as they cool.
Cool and Finish: Allow the cookies to cool on the baking sheet for 5 minutes before carefully transferring them to a wire rack to cool completely. Dust lightly with powdered sugar before serving if desired.
Method 1: Freezing the Raw Dough (Recommended)
Shape and Fill: Follow the recipe instructions to roll the raspberry dough into balls, press the center wells, and fill each well with the (\frac{1}{2}) teaspoon of lemon curd.
Flash Freeze: Place the filled, unbaked cookies onto a parchment-lined baking sheet close together (but not touching). Put the tray in the freezer for 2 hours until the cookies and the curd centers are frozen completely solid.
Bag and Store: Peel the frozen cookies off the parchment and transfer them into a heavy-duty zip-top freezer bag. Squeeze out as much air as possible. They will keep perfectly for up to 3 months.
How to Bake: Bake directly from frozen! Place them on a lined baking sheet and bake at 350°F (177°C) for 12 to 14 minutes (just add 1 to 2 extra minutes to the original baking time).