Prepare the Cake

Preheat the oven and prepare the pan.

• Preheat the oven to 350°F. Grease a 9x13-inch baking pan with cooking spray.

Mix the batter.

• In a large mixing bowl, combine the white cake mix, eggs, water, canola oil, and tequila. Using a hand mixer or stand mixer, beat until the batter is smooth and fully combined.

Add the blackberries.

• Gently fold the blackberries into the batter until evenly distributed.

Bake the cake.

• Pour the batter into the prepared baking pan and spread evenly. Bake for 30 to 35 minutes, or until the cake is fully baked and a toothpick inserted into the center comes out clean.

Cool the cake.

• Transfer the cake to a cooling rack and allow it to cool slightly.

Prepare the Frosting

Heat the butter and milk.

• In a saucepan over medium heat, combine the butter and milk. Bring the mixture to a boil, stirring frequently.

Finish the frosting.

• Remove the saucepan from the heat. Stir in the confectioners’ sugar, lime extract, tequila, and lime zest until smooth.

Frost the cake.

• Spread the frosting over the slightly warm cake in an even layer.

Decorate the Cake

Add the blackberry sauce.

• Pipe or drizzle horizontal lines of blackberry dessert sauce across the top of the frosted cake.

Create the design.

• Using a sharp knife or butter knife, drag the blade vertically through the lines to create a decorative pattern. Alternatively, drizzle the blackberry sauce freely over the top for a simpler finish.

Serve.

• Slice the cake and serve.