Created by KittenCal on September 13, 2011
Step 1: Preheat oven to 350 degrees F. Position oven rack to lowest position.
Step 2: Grease an 9-inch or an 11 x 7-inch baking dish.
Step 3: Cook spaghetti according to package directions; drain, rinse under cold water and drain well again; transfer to a medium or large heat-proof bowl. Set aside.
Step 4: Cook ground beef with onion in a large skillet stirring until meat browns (about 10-12 minutes).
Step 5: Add in garlic; continue cooking for another 2 minutes; drain fat.
Step 6: Stir in the chili powder, smoked paprika, Worcestershire sauce, ketchup, mustard, 1 cup beef broth, cheese slices, salt and pepper into the meat mixture; simmer covered with a lid or partially covered over medium-low heat for about 20-22 minutes, stirring frequently (no more than 20-22 minutes or it will reduce too much).
Step 7: Stir in cooked spaghetti (I suggest you allow mixture to cool and use your hands or a large tong for mixing, I use my hands).
Step 8: Transfer/spread the mixture into a baking dish.
Step 9: Top spaghetti with 1 cup shredded cheddar cheese then 1/2 cup shredded mozzarella (can use more cheese) *** at this point you can cover and refrigerate up to 48 hours or until ready to bake, leave out on counter for one hour or a little more before baking).
Step 10: Bake about 30 minutes, or until hot and bubbly and cheese begins to brown.