Wash and dry all produce. Adjust racks to middle and upper positions and preheat oven to 450 degrees. Bring a medium pot of salted water to a boil. Halve zucchini lengthwise, then cut crosswise into 1/4-inch-thick half-moons. Mince or grate garlic. Slice sweet potatoes into 1/4-inch-thick rounds. Once water boils, add fusilli to pot. Cook, stirring occasionally, until al dente, 9-12 minutes, then drain.

Heat a drizzle of oil in a large ovenproof pan over medium-high heat. Add zucchini and cook until tender, 4-5 minutes. Remove from pan and set aside. Heat another drizzle of oil in same pan over medium-high heat. Add garlic and cook until fragrant, about 30 seconds. Add half the beef, breaking up meat into pieces. Cook until browned, 5-6 minutes. Drain any excess grease. Season beef with plenty of salt and pepper. Toss in zucchini and Tuscan heat spice.

While beef cooks, toss sweet potatoes on a baking sheet with a drizzle of oil. Season with salt, pepper, and thyme. Roast in oven on upper rack until tender and lightly crisped, 20-25 minutes, tossing halfway through. Measure out 1/4 cup marinara sauce and place in a small bowl. Stir in a pinch of salt and pepper. Set aside. After adding zucchini and spice to pan, stir in milk and remaining marinara sauce. Bring to a simmer. Cook until slightly reduced, 2-3 minutes.

Lower heat under pan to medium. Stir in fusilli. Season with salt and pepper. Remove from heat. (TIP: If your pan isn’t ovenproof, transfer pasta to a baking dish.) Sprinkle half the mozzarella over pasta. Bake on middle rack of oven until cheese melts, 5-7 minutes. Set aside to cool. Split buns in half and toast in oven or toaster until golden, 2-3 minutes. Shape rest of beef into two patties and season with salt and pepper.

Heat a drizzle of oil in a large pan over medium-high heat. (TIP: You can clean and use the one used for the pasta if it’s available.) Add patties to pan and cook until just shy of desired doneness, 3-5 minutes per side. Top with reserved 1/4 cup marinara sauce and sprinkle with remaining mozzarella. Cover pan and let cheese melt, 1-2 minutes. Fill buns with patties, divide between plates, and serve with sweet potatoes.

Divide pasta between two reusable containers. Keep refrigerated until lunchtime. When ready to eat, microwave on high until warmed through, 2-3 minutes.