Before starting, preheat the oven to 450˚F. Wash and dry all produce. Garlic Guide for Step 5 (dbl for 4 ppl): 1/4 tsp mild, 1/2 tsp medium and 1 tsp extra! Add 10 cups water and 2 tsp salt to a large pot (use same for 4 ppl). Cover and bring to a boil over high heat. While water comes to a boil, cut tomato into 1/2-inch pieces. Peel, then cut half the onion into 1/2-inch pieces (use whole onion for 4 ppl). Roughly chop spinach. Cut mozzarella into 1/2-inch pieces. Peel, then mince or grate garlic.

Add penne to the boiling water. Cook uncovered, stirring occasionally, until tender, 10-12 min. Reserve 1/4 cup pasta water (dbl for 4 ppl), then strain and return penne to the same pot, off heat.

Heat a large non-stick pan over medium. When hot, add 1 tbsp oil (dbl for 4 ppl), then onions. Cook, stirring often, until softened, 2-3 min. Add tomato sauce base, tomatoes, spinach, half the garlic and 2 tsp Italian Seasoning (dbl for 4 ppl). Cook, stirring often, until fragrant, 1-2 min.

Add 2 tbsp oil (dbl for 4 ppl), remaining Italian Seasoning and 1/4 tsp garlic to a medium bowl. (NOTE: Reference garlic guide.) Add mozzarella. Season with salt and pepper, then gently stir to coat. Halve ciabatta. Arrange ciabatta on an unlined baking sheet, cut-side up, then top with half the mozzarella. Toast in the middle of the oven until cheese melts, 3-4 min. (TIP: Keep an eye on them so they don't burn!)

Add sauce, reserved pasta water, pesto and half the Parmesan to the pot with penne. Stir to coat, 1-2 min. Cut garlic ciabatta into triangles. Divide penne between plates. Top with remaining mozzarella. Sprinkle with remaining Parmesan and chili flakes, if desired. Serve garlic ciabatta alongside.