Cookie 1: Brown Sugar Spice Cookies

1. Preheat the oven to 350°F and line two baking sheets with parchment paper.
2. In a large bowl, stir together the cake mix, brown sugar, oil, eggs, vanilla, and ginger until fully combined.
3. Chill the dough for 15–20 minutes to help with spreading.
4. Scoop dough into 1.5-tablespoon balls and space about 2 inches apart on the baking sheet.
5. Bake for 8–10 minutes, until the edges are set and the tops look soft but no longer glossy.
6. Let cool completely.

Cookie 2: Green Vanilla Cake Batter Cookies

1. Preheat oven to 350°F and line two baking sheets with parchment paper.
2. In a bowl, combine the cake mix, oil, eggs, vanilla, and food coloring until a soft dough forms.
3. Fold in sprinkles, if using.
4. Scoop into 1.5-tablespoon balls and bake for 8–10 minutes, until the edges are lightly golden and the tops are set.
5. Cool completely before assembling.

Dulce de Leche Sea Salt Buttercream

1. Beat the softened butter until creamy.
2. Add the dulce de leche and sea salt and beat until smooth.
3. Gradually mix in the powdered sugar until fluffy.
4. If needed, add cream 1 teaspoon at a time until it reaches a pipeable consistency.

To Assemble

1. Lay the brown sugar cookies flat-side up on a cutting board or tray.
2. Pipe or spoon a swirl of buttercream onto each one.
3. Gently press a green vanilla cookie on top of each to create a sandwich.
4. Repeat with the remaining cookies until all sandwiches are assembled.