Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In another bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the milk until just combined.

Divide the batter evenly between the prepared cake pans and smooth the tops.

Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean. Let cool in the pans for 10 minutes before transferring to wire racks to cool completely.

In a mixing bowl, beat the softened butter until creamy. Gradually add the powdered sugar and mix until smooth.

Add the vanilla extract and milk, mixing until the frosting is fluffy. Divide the frosting into two bowls and tint one with green food coloring and the other with blue.

Once the cakes are completely cool, place one layer on a cake stand and spread a layer of green frosting on top.

Place the second cake layer on top and frost the entire cake with the blue frosting.

Decorate the top with dinosaur cake toppers and sprinkle candy rocks around the base.