1. Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with olive oil.
2. If using frozen meatballs, thaw them according to package instructions. If homemade, cook them in a skillet with 1 tablespoon of olive oil over medium heat until browned and cooked through, about 8-10 minutes. Set aside.
3. In a medium saucepan, heat the marinara sauce with minced garlic and Italian seasoning over low heat until warmed through. Taste and adjust salt and pepper if needed.
4. Place the bread cubes in the prepared baking dish, spreading them evenly. Drizzle with the remaining tablespoon of olive oil and toss gently to coat. This helps the bread soak up the sauce without becoming mushy.
5. Layer half of the meatballs over the bread cubes, then pour half of the marinara sauce evenly over the top. Sprinkle half of the mozzarella, provolone, and Parmesan cheeses.
6. Repeat the layering with the remaining meatballs, marinara, and cheeses.
7. Cover the dish tightly with foil and bake for 25 minutes. Then remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden brown.
8. Let the casserole rest for 5-10 minutes before serving. This resting time allows the sauce to thicken slightly and makes it easier to scoop out portions.

One tip from my early kitchen days: don’t rush the resting stage. I learned the hard way with a chili that was too soupy when eaten immediately. Taking the time to let a dish settle can make all the difference in texture and flavor.