Preheat the oven to 350 degrees F.
In a large bowl, combine the ground beef, ground pork, egg, tomato sauce, onion, mustard, garlic, salt, pepper. Mix until well combined.
Line an 8 inch, 6 inch and 3 inch cake pan with parchment paper and place mixture into the pans.
Place in the oven and cook the 3 inch meatloaf cake for 15 minutes or until cooked through and no longer pink inside. Cook the 6 inch meatloaf cake for 30 minutes or until cooked through and no longer pink inside. Cook the 8 inch meatloaf cake for 45-55 minutes or until cooked through and no longer pink inside.
Meanwhile, make the sauce: Place the butter in a saucepan and heat until the butter sizzles and brown flecks appear, stirring constantly to keep the butter from burning. Reduce the heat to low. Whisk in the cream cheese and broth. Use a stick blender to puree until smooth.
When the meatloaf is done, remove them from the oven. Allow to cool for 30 minutes in the fridge, so the frosting doesn't melt when you place it onto the meatloaf cake.
Once the meatloaf is cool, trim the top of the cakes so that they are flat on the top and bottom.
Place the 8 inch meatloaf cake on the bottom of a serving platter and use a knife to cover with frosting.
Place the 6 inch meatloaf cake on top of the frosted 8 inch meatloaf cake and use a knife to cover in frosting. Repeat with the 3 inch meatloaf cake.
Place in the fridge to chill until serving.
Just before serving, place a large knife into the center of the top of the cake. Pour the ketchup on the top of the cake and use a spoon to slide it down the slices to look like blood.
To serve, reheat slices in a casserole dish in a 350 degree F oven for 5 minutes or until heated through.