Adjust rack to top position and preheat oven to 450 degrees. Bring a large pot of salted water to a boil. Wash and dry produce. 

Once water is boiling, add penne to pot. Cook, stirring occasionally, until al dente, 9-11 minutes. Drain.

While pasta cooks, heat a drizzle of oil in a large pan over medium-high heat. 

Add pork* and cook, breaking up meat into pieces, until browned and cooked through, 4-6 minutes. 

Season with Tuscan Heat Spice, salt, and pepper. Stir to combine.

Stir marinara sauce and half the milk (all for 8 servings) into pan with pork. Cook, stirring occasionally, until sauce begins to bubble, then remove from heat.

Stir in spinach and as many chili flakes as you like. Cover pan until spinach wilts. Stir in half the mozzarella. Taste and season with salt and pepper. 

Transfer drained penne to a 9-by-13-inch baking dish (two 9-by-13-inch baking dishes for 8 servings).

Carefully pour sauce over pasta and stir until sauce is evenly distributed.

Evenly top pasta mixture in baking dish with panko, remaining mozzarella, and a large drizzle of olive oil. 

Bake until panko is browned and crispy, 12-15 minutes.

Divide casserole between plates or serve family style directly from baking dish.