Prepare the Casserole: Preheat the oven to 400°F (200°C). Slice the potatoes, zucchini, and red onions thinly. In a baking dish, layer these vegetables with tomatoes, and drizzle with olive oil. Season with salt, pepper, and parsley.

Bake the Casserole: Cover the dish and bake for 1.5 hours, stirring halfway through to ensure even cooking. Bake until vegetables are tender and edges are golden brown.

Make Cheesy Tomato Potatoes: In a skillet, heat olive oil and butter over medium heat. Add diced Yukon gold potatoes, season with Adobo, and cook covered for about 10 minutes, flipping halfway.

Add Sauce and Cheese: Add spaghetti sauce to the potatoes and cook for another 4 minutes. Sprinkle with shredded provolone or other cheese. Cover briefly to melt the cheese.

Serve: Garnish with fresh parsley and serve with salad or crusty bread.