Wash and dry all produce. Preheat broiler to high or oven to 500 degrees. Bring a large pot of salted water to a boil. Mince or grate garlic. Roughly chop parsley. Once water is boiling, add macaroni to pot. Cook, stirring occasionally, until al dente, 9-11 minutes. Drain.

Place 1 TBSP butter in a small bowl. Microwave on high until melted, about 20 seconds. (TIP: Alternatively, melt butter in a small pan.) Add panko and half the parsley to bowl and stir to combine. Season with salt and pepper.

Heat a drizzle of oil in a large, tallsided pan over medium-high heat (use an ovenproof pan if you have one). Add pancetta and cook, tossing, until crisp, 4-5 minutes. Transfer to a paper-towel lined plate with a slotted spoon, keeping as much oil in pan as possible.

Lower heat under pan to medium. Add garlic and cook until fragrant, about 30 seconds. Add flour and cook, stirring constantly, until it loses its raw smell, about 1 minute. Slowly pour in 2 cups milk (we sent more), whisking vigorously to incorporate. Bring to a gentle boil and cook until thickened, 1-2 minutes. Remove from heat, then add Parmesan and stir until melted.

Add tomatoes and spinach to pan. Stir to wilt spinach (if leaves do not wilt, return pan to medium heat). Season with salt and pepper. Stir in drained macaroni, pancetta, and remaining parsley. Season with salt and pepper. (TIP: If your pan is not ovenproof, transfer mixture to a small baking dish at this point.)

Sprinkle crust mixture over top of pasta. Broil or bake until crust is golden, 2-3 minutes. Divide pasta between plates and serve.