Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9-inch square cake pans.
Sift 2 1/3 cups plus 1 1/2 tablespoon flour, 1/2 cup plus 3 tablespoons cocoa powder, baking powder, and salt together in a large bowl.
Beat butter and white sugar together in a bowl with an electric mixer until light and fluffy, about 4 minutes. Add eggs, one at a time, beating well after each addition. Beat in vanilla extract. Add flour mixture alternately with 1 cup plus 1 1/2 tablespoon milk, mixing batter gently between each addition.
Divide batter evenly between the prepared cake pans.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 30 to 40 minutes. Cool for 10 minutes in the pan. Invert onto a wire rack to cool completely, about 30 minutes.
Trim tops of cake layers to make sure they are flat. Set 1 layer on a serving platter. Spread jam on top; cover with second layer. Spread chocolate buttercream frosting over top and sides of the cake, reserving about 2 tablespoons frosting.
Pinch off a piece of marzipan the size of a golf ball. Add red food coloring and knead until color is evenly distributed.
Dust a flat work surface with confectioners' sugar and roll out remaining, undyed, marzipan. Cut out a 9-inch square; carefully transfer to the top of the cake.
Roll trimmings of marzipan and cut into four 9x1-1/2-inch strips. Cut 3 rectangular notches into 1 edge of each strip. Press strips onto the sides of the cake, notches facing down; gently press top and strips of marzipan together to adhere.
Roll out red marzipan and cut into squares of varying sizes. Spread a little of the reserved frosting on the back of each square to act as a glue; arrange in a random Minecraft pattern on top of the cake.
Substitute strawberry jam for the cherry jam if desired. You can also sandwich the layers together with buttercream instead of jam.
Instead of marzipan, you could use 14 ounces of store-bought white fondant icing instead. You can decorate the cake further with Minecraft cake toppers, available online, or you could even use the Minecraft LEGO® Steve and Creeper figurines.