Ingredients
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Dried spaghetti — 1 lb
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Unsalted butter — 3 Tbsp
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All-purpose flour — 3 Tbsp (for the roux)
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Whole or 2% milk — 3 cups (room temp for smooth blending)
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Heavy cream — 1 cup (up to 2 cups for extra richness)
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Low-moisture mozzarella, shredded — 6 oz (about 1½ cups), divided
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Parmesan, finely grated — 4 oz (about 1½ cups), divided
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Garlic powder — ½ tsp
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Kosher salt — 1 tsp, plus more for pasta water
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Parsley, finely chopped — optional, for serving
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Reserved pasta water — up to ½ cup (as needed)
Instructions
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Heat oven & boil pasta: Preheat to 375°F (190°C). Boil spaghetti in well-salted water 2 minutes shy of al dente. Reserve ½ cup pasta water; drain.
Tip: Slightly undercooking prevents a mushy bake. -
Make a pale roux: In a wide saucepan over medium heat, melt 3 Tbsp butter. Whisk in 3 Tbsp flour for 1–2 minutes until foamy and fragrant (do not brown).
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Whisk in dairy: Gradually whisk in 3 cups milk, then 1 cup cream. Simmer, whisking, until it coats a spoon (5–7 minutes). Stir in ½ tsp garlic powder and 1 tsp salt.
Tip: If lumpy, whisk vigorously or blitz 10 sec with an immersion blender. -
Turn béchamel into Alfredo: Reduce heat to low. Add half the mozzarella and half the Parmesan a handful at a time, whisking smooth after each addition. Adjust salt to taste.
Tip: Keep heat low to avoid grainy cheese. -
Coat the pasta: Toss spaghetti with the sauce until glossy. Loosen with 1–3 Tbsp reserved pasta water if needed—sauce should cling, not pool.
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Assemble: Lightly grease a 9×13-inch baking dish. Add pasta. Top evenly with remaining mozzarella and Parmesan.
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Bake: Bake 15–18 minutes until edges bubble and top is spot-browned. For deeper color, broil 1–2 minutes (watch closely). Rest 5 minutes; finish with parsley.
Notes
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Make-ahead: Assemble up to 1 day ahead; cover and refrigerate. Add 5–10 minutes to bake time.
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Add-ins: Fold in shredded rotisserie chicken, sautéed mushrooms, spinach, or steamed broccoli.
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Cheese swaps: Asiago or Pecorino Romano can replace part of the Parmesan for a sharper bite.
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Texture key: Undercook pasta slightly and keep roux pale for the creamiest white sauce.
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Storage: Refrigerate 3–4 days. Reheat covered at 325°F (165°C) with a splash of milk.
- Prep Time: 15 minutes
- Cook Time: 40 minutes
- Category: Dinner; Pasta; Casserole
- Method: Baking; Oven
- Cuisine: American-Italian
Nutrition
- Serving Size: 1/8 of recipe
- Calories: 520 kcal
- Sugar: 7 g
- Sodium: 820 mg
- Fat: 25 g
- Saturated Fat: 14 g
- Unsaturated Fat: 10.5 g
- Trans Fat: 0.5 g
- Carbohydrates: 57 g
- Fiber: 2 g
- Protein: 21 g
- Cholesterol: 85 mg