Drain very wet ricotta in a sieve for 20-30 minutes. Heat the oven to 350°F (175°C), then grease and line a 9-by-13-inch baking pan.

Whisk the flour, cocoa powder, baking powder, baking soda, and salt together in a medium bowl. This distributes the leaveners evenly through the chocolate batter.

Beat the softened butter and granulated sugar until light. Add the eggs one at a time, mixing after each addition, then blend in the ricotta and vanilla.

Add the dry ingredients alternately with the milk or buttermilk, mixing only until combined. Spread the batter evenly in the prepared pan.

Bake for 30-40 minutes, until the center springs back and a toothpick comes out with a few moist crumbs. Cool the cake completely in the pan before frosting.

Beat the frosting butter, confectioners’ sugar, cocoa powder, vanilla, salt, and 3 tablespoons of milk or cream until smooth. Add the remaining milk or cream gradually until the frosting is spreadable.

Spread the frosting over the completely cooled cake. Crush the chocolate sandwich cookies and scatter the crumbs over the frosting to make the graveyard soil.

Write RIP on the chocolate cookie tombstones with melted white chocolate or decorating icing. Insert the tombstones into the cake, then arrange candy pumpkins, gummy worms, candy bones, and optional wafer-cookie or pretzel fences.