Ingredients

• 450 g pasta tubessturdy tubes such as rigatoni, so the sauce lodges inside
• 500 g chestnut mushrooms
• 35 g butter
• 1 tbsp olive oil
• 3 garlic cloves
• 300 ml double cream
• 200 ml vegetable stock
• 180 g Gruyere
• 50 g Parmesan
• 1 tsp thyme
• 1 1/4 tsp fine salt and freshly ground black pepper

Method

1. 01

   Undercook the pasta

   Cook the 450 g pasta in well-salted water for 2 minutes less than the packet says. It should still be firm in the middle. It finishes in the oven, and pasta drained at al dente ends up soft in a bake. Reserve a mugful of the cooking water before draining.

2. 02

   Brown the mushrooms in batches

   Heat the olive oil in a wide pan over medium-high and cook the mushrooms in two or three batches, unsalted, leaving each batch undisturbed for 2-3 minutes before stirring. Cook until the water has gone and the edges are dark, 6-8 minutes a batch. Crowded pale mushrooms leak water into the bake and lose all their savoury intensity.

   1 tbsp olive oil · 500 g chestnut mushrooms

   Batches, every timeFive hundred grams will not brown in one pan. They stew themselves and the bake goes watery.

3. 03

   Build the sauce

   Return all the mushrooms, add the butter, the grated garlic cloves and thyme and cook for a minute until fragrant. Pour in the stock and cream and simmer over medium-low for 4-5 minutes until lightly thickened. Stir in half the 180 g Gruyere and half the 50 g Parmesan off the boil so they melt smoothly.

   35 g butter · 3 garlic cloves · 1 tsp thyme · 200 ml vegetable stock · 300 ml double cream · 180 g Gruyere · 50 g Parmesan

   Cheese off the boilAt a rolling simmer Gruyere splits and the sauce turns oily.

4. 04

   Combine

   Fold the drained pasta through the sauce, loosening with the reserved pasta water until it looks a little wetter than you want the finished dish. The pasta will absorb the difference in the oven. Season.

   Sauce it wetter than you thinkThe pasta keeps drinking in the oven. What looks right in the pan comes out dry.

5. 05

   Bake

   Transfer to a buttered baking dish, scatter over the remaining cheeses and bake at 210 C / 190 C fan for 18-22 minutes, until bubbling at the edges and deeply blistered on top.

6. 06

   Rest

   Rest for 5 minutes before serving so the sauce settles and stops running across the plate.