Coat four 9-inch-round cake pans with cooking spray and prepare the cake mixes as directed (or coat 2 pans and make the cakes in 2 batches). Divide the batter among the pans and bake as directed. Let cool 20 minutes, then remove from the pans and let cool completely.
Stack the cakes on an upside-down cake pan, spreading frosting between the layers. Freeze 30 minutes. Using a small serrated knife, trim the bottom 2 layers of the cake on an angle to resemble the bottom of an apple.
Trim the top layer just enough to round the edge, then carve out a 3-inch-wide cone-shaped piece of cake from the middle where the stem would be (about1 1/2 inches deep). Gather all of the cake trimmings in a bowl.
Crumble the cake trimmings and mix with just enough frosting to moisten. Clump the mixture together and mound in a ring around the hole to form the top of the apple.
Cover the cake with a thin layer of frosting (this is the crumb coat-it doesn't have to be perfect). Freeze 20 minutes. Remove from the freezer and completely cover the top 4 inches of the cake and inside the cavity with more frosting.
Mix the red food coloring with a dash of vanilla. Use a pastry brush to paint the top few inches of the cake a streaky red, blotting the brush on paper towels as needed. Repeat with the yellow food coloring to add a few yellow streaks.
Unwrap the caramels and microwave until soft but not melted, about 20 seconds. Gather together, then flatten into a rectangle with your hands. Roll out on parchment paper to make a 7-by-26-inch rectangle, stretching with your hands as needed.
Lightly brush the caramel rectangle with water where you want the peanuts to go. Sprinkle the nuts on top, then press them in with the rolling pin.
Transfer the cake to a flat platter or sheet of parchment using your hands (don't touch the red part). Wrap the caramel around the cake, leaving the red top exposed. Tuck the caramel around the bottom of the cake; trim the excess with a knife so it looks like a pool of caramel. Insert a dowel into the top.