Before starting, preheat the oven to 450˚F. Wash and dry all produce.Garlic Guide for Step 3: ¼ tsp (½ tsp) mild, ½ tsp (1 tsp) medium and 1 tsp (2 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. Meanwhile, peel, then cut shallot into ¼-inch pieces. Roughly chop spinach. Cut mozzarella into ½-inch pieces. Peel, then mince or grate garlic.
Add penne to the boiling water. Cook uncovered, stirring occasionally, until tender, 10-12 min. Reserve ⅓ cup (⅔ cup) pasta water, then drain and return penne to the same pot, off heat.
Meanwhile, add 2 tbsp (4 tbsp) oil, 1 tsp (2 tsp) Italian Seasoning and ¼ tsp (½ 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 on an unlined baking sheet, cut-side up, then top with half the marinated mozzarella.Toast in the middle of the oven until cheese melts, 4-6 min. (TIP: Keep an eye ciabatta so they don't burn!)
Heat a large non-stick pan over medium heat. When hot, add 1 tbsp (2 tbsp) oil, then shallots. Cook, stirring often, until softened, 2-3 min. Add cream cheese, spinach, remaining garlic and 2 tsp (1 tbsp) Italian Seasoning. Cook, stirring often, until fragrant and cream cheese softens, 1-2 min.
Add sauce, reserved pasta water, sun-dried tomato pesto and half the Parmesan to the pot with penne. Season with salt and pepper, to taste, then stir to coat, 1-2 min.
Cut garlic ciabatta into triangles.Divide penne between plates. Top with remaining marinated mozzarella.Sprinkle with remaining Parmesan and chili flakes, if desired.Serve garlic ciabatta alongside.