Butternut Leek Rigatoni Gratin
By Emma
Certified Culinary Professional
•
Recipe tested & approved
Roasted butternut squash cubes blended into a creamy leek sauce coat al dente rigatoni and fresh spinach. Topped with a sharp cheddar and Parmigiano crust, baked until golden. Aromatic garlic and onion anchor a velvety béchamel enriched with chicken broth and milk. Optional heat from chili flakes and a hint of nutmeg bring depth. Comfort food with a twist—a perfect balance of sweet squash and savory greens. Suitable for nut- and egg-free diets. Makes 8 to 10 portions, great for family meals or gatherings.
Prep:
30 min
Cook:
50 min
Total:
Servings:
8 to 10 servings
#comfort food
#French-inspired
#vegetarian option
#baked pasta
#fall recipes
Roasting squash transforms it—the smell, that caramelized sweetness. Then mixing with leeks softened slowly in butter, onions and garlic sneaking into the background. Pasta almost forgotten in boiling water while I mind sauce thickness. Spinach tucked in last minute, wilting where warmth meets green freshness. Cheese on top turns golden, blistered, the scent filling the kitchen with nostalgia. My early attempts failed—pasta mush, bland sauce, over-spiced piment killed subtleties. Learned the hard way: watch the squash edges, don’t rush purée smoothness, timing on pasta is everything. That crunch of baked cheese, the softness beneath—a stroll through comfort with some finesse. Every forkful a layered memory: bite, chew, savor. Not fancy, just honest food done right.
Ingredients
- 900 ml (3 3/4 cups) butternut squash peeled, seeded, cut into chunks
- 30 ml (2 tbsp) olive oil
- 380 g (about 3/4 lb) rigatoni pasta
- 700 ml (about 3 cups) sliced leeks (1 to 2 medium-sized)
- 1 small onion, finely chopped
- 2 garlic cloves, minced
- 60 ml (1/4 cup) unsalted butter
- 65 ml (1/4 cup plus 1 tsp) all-purpose flour
- 475 ml (2 cups) chicken broth
- 275 ml (1 1/8 cups) whole milk
- 1.8 liters (about 7 cups) fresh baby spinach, stemmed and roughly chopped
- Pinch red chili flakes (optional)
- Grated nutmeg, a light dusting (optional)
- 220 ml (7/8 cup) shredded sharp cheddar cheese
- 130 ml (just over 1/2 cup) grated Parmigiano Reggiano
- Salt and pepper
About the ingredients
Butternut squash chosen for sweetness and creamy texture, but pumpkin or kabocha work if you adjust roasting times. Olive oil drizzle helps browning and flavor, butter in sauce adds silkiness plus leeks, onions, garlic bring aromatic base—don’t skip or replace with powdered. Chicken broth lends depth; vegetable broth fine as swap but flavors shift slightly. Milk balances thickness and lightness of sauce; whole milk best for creaminess. Fresh spinach gives vibrant color and freshness; frozen can work but drains must be thorough to avoid soggy mix. Cheese blend critical: sharp cheddar for punch, Parmesan for nuttiness—use good quality, freshly grated; pre-grated has anti-caking agents that affect melt. Salt and pepper essential seasoning anchors whole dish. Optional punch from chili flakes and nutmeg—add carefully, you want subtle warmth not fire or spice overload.
Method
- Set oven rack to middle position. Preheat oven to 210 C (410 F). Line baking sheet with parchment paper.
- Scatter squash cubes on sheet. Drizzle olive oil, season with salt and pepper; toss to coat evenly. Roast about 22 minutes, stirring halfway, until tender, golden edges forming. Don’t overcook or squash loses shape and flavor goes flat. Let cool.
- Meanwhile, bring large pot of salted water to boil. Cook rigatoni just under al dente — firm with slight bite — drain, drizzle a touch of oil to prevent sticking. Set aside covered to keep warm.
- Use same large pot. Melt butter over medium heat. Add leeks, onion, garlic; sweat gently with a pinch salt till translucent, about 8 minutes. Don’t brown—no bitterness. Sprinkle flour evenly, cook stirring for 1 minute to get rid of raw taste.
- Gradually whisk in chicken broth and milk. Bring to soft boil, then reduce heat and simmer until sauce thickens, bubbles coat spoon, about 6 minutes. Sauce should be creamy, not too thick or thin. Taste for seasoning.
- Remove from heat. Use immersion blender for smooth leek purée. Don’t leave chunks—they create uneven texture. Fold in roasted squash, cooked pasta, and chopped spinach while still warm. Spinach wilts gently in residual heat—if you add raw, it tastes grassy and bitter.
- Adjust seasoning—salt, pepper, and optional chili flakes and nutmeg. These add surprising warmth and lift. Mix well but gently, keep pasta intact.
- Transfer mixture to 33 x 23 cm (13 x 9 inch) ovenproof dish. Spread evenly. Top with cheddar and Parmigiano. Cheese blend gives sharpness and nutty crust. Don’t skimp or gratin lacks character.
- Bake for 24 to 27 minutes until cheese bubbles and develops golden-brown spots. Edges crisp up—listen for slight crackle. Overbaking dries it; underbaking leaves sauce runny. Let rest 15 minutes before serving to set. The gratin firms, flavors meld.
- Serving tip: spoon out with metal spatula scraping crispy cheese bits underneath. Perfect alongside simple salad or roasted ham.
- Substitutions: Swap chicken broth for vegetable broth for vegetarian option. Use Gruyère or Fontina in place of cheddar for a milder cheese note. If you want vegan, replace butter with plant-based margarine and milk with unsweetened oat milk; omit cheeses or use vegan alternatives though texture will differ.
- Common issues: Overcooked pasta turns gummy—always undercook by a minute or two. If sauce too thick before baking, thin with splash more milk or broth; too thin, simmer longer to reduce. Squash should be fork-tender but hold shape—mushy cubes won’t roast well or puree smoothly.
- Efficiency tip: Roast squash and cook pasta simultaneously to cut total time. Prepare sauce while those roast and boil. Saves waiting around, gets everything hot and ready faster.
Cooking tips
Preheat oven all in once to save time; check roast at half point, stir to prevent burning. Pasta timing critical—start boiling water early, test doneness by biting into it; should resist slightly. While pasta cooks, sweat veggies low and slow in butter—avoid burning or browning to keep flavors sweet, not bitter. Flour cooking: stir fast to avoid lumps and raw flour taste; slowly add liquids off heat for smooth béchamel. Immersion blender gives silky sauce texture but don’t over blend past the point—some thickness is good. Fold roasted squash and spinach gently into sauce/pasta mix to keep texture. Cheese topping spreads evenly; don’t pile too thick or it won’t brown properly. Bake monitored closely—cheese golden and bubbling is your cue. Resting is key—grab a drink, start plating sides. Speaking from many batches—these times are guidelines; smell, sight, touch are kitchen language here.
Chef's notes
- 💡 Roast squash cubes without overcrowding. Spread single layer, toss halfway. Watch edges for golden spots, smell changes. Don’t overcook or mush sets texture off. Let cool before folding or sauce thins.
- 💡 Pasta timing critical. Underboil rigatoni by a minute or two. It continues cooking in sauce and oven. Drain, drizzle with oil to stop sticking. Keep covered to conserve heat and texture before mixing.
- 💡 Sweat leeks low and slow in butter with onion and garlic. Must stay translucent, no color. Brown brings bitterness. Stir flour in quickly off heat to avoid raw taste. Whisk liquids gradually, keep sauce creamy with right thickness.
- 💡 Immersion blend sauce till silky but not puree mushy. Some texture makes sauce interesting. Fold in roasted squash and spinach gently. Warm sauce wilts spinach without turning bitter, raw leaves mean grassiness.
- 💡 Cheese topping crucial. Blend sharp cheddar and Parmigiano freshly grated—avoid pre-grated powdery. Sprinkle evenly, don’t overload or crust won’t brown properly. Bake till golden bubbling edges crisp, listen for crackle cues.
Common questions
Can I swap chicken broth?
Vegetable broth works fine. Flavor shifts slightly but saucy texture same. Lentil or mushroom broth also okay. If vegan, use broth + tweak seasoning.
How to fix sauce too thick or thin?
Add splash milk or broth for thinning. If too runny, simmer longer on low heat. Watch edges for clingy coating spoon trick. Thickness affects final bake texture.
What causes gummy pasta?
Overcooking pasta in boiling water or post-bake. Undercook by minute or two always. Also, acid in sauce or too dry can ruin. Toss with tiny oil after draining prevents sticking.
Best way to store leftovers?
Refrigerate airtight container up to 3 days. Reheat covered in oven or microwave, add splash milk if drying out. Freezing alters texture; bake fresh preferred for crust crispness.
