Preheat the oven to 350°F (175°C). Grease and flour a cake pan.

In a mixing bowl, cream together the butter and 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, combine the flour, baking powder, and salt. Gradually add to the creamed mixture alternately with milk.

Pour the batter into the prepared cake pan and smooth the top.

Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes, then turn out onto a wire rack to cool completely.

In a mixing bowl, beat together the softened butter and powdered sugar until smooth.

Add milk and vanilla extract, mixing until the frosting is creamy. Add green food coloring to achieve the desired color.

Once the cake is completely cool, frost the top and sides with the green frosting.

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