Preheat oven to 350°F (175°C). Grease two 9-inch round cake pans and line with parchment paper.

Cream butter and sugar: In a large bowl, beat 1 cup softened butter and 2½ cups granulated sugar until fluffy (3-5 minutes).

Add eggs: Mix in 4 eggs, one at a time, followed by 2 tsp vanilla extract.

Combine dry ingredients: In a separate bowl, whisk 3 cups flour, 2½ tsp baking powder, and ½ tsp salt.

Alternate wet and dry: Gradually add dry ingredients to the butter mixture, alternating with 1 cup milk. Mix until just combined.

Fold in chocolate chips: Toss 1 cup mini chocolate chips in 1 tbsp flour (to prevent sinking), then gently fold into the batter.

Bake: Divide batter evenly into pans. Bake 25-30 minutes until a toothpick comes out clean. Cool in pans for 10 minutes, then transfer to a wire rack.

Whip butter: Beat 4 cups softened butter on medium speed until pale and creamy (5 minutes).

Add sugar: Gradually mix in 8 cups powdered sugar, 1 cup at a time.

Flavor and color: Add 2 tbsp vanilla extract and ¼ cup heavy cream. Mix in royal blue gel food coloring until vibrant.

Adjust consistency: Add more cream (1 tbsp at a time) if too thick, or powdered sugar if too runny.

Level the cakes: Use a serrated knife to trim domed tops for flat layers.

Layer and fill: Place one cake layer on a plate. Spread a thick layer of frosting, then top with the second layer.

Crumb coat: Apply a thin layer of frosting over the entire cake. Chill for 20 minutes.

Pipe the "fur": Fit a piping bag with a grass tip (#233). Pipe blue frosting in short bursts to create a furry texture, covering the entire cake.

Add eyes and cookies: Attach edible googly eyes with frosting. Press chocolate chip cookies into the sides and top. Sprinkle cookie crumbs around the base.