Caramelize the onions

• Melt part of the butter in a large sauté pan over medium-low heat.
• Add the sliced onions with a pinch of salt and cook slowly, stirring occasionally, until deep golden and jammy.

Cook the rigatoni

• Bring a large pot of salted water to a boil and cook the rigatoni until just shy of al dente.
• Reserve a cup of pasta water, then drain.

Build the pumpkin cream sauce

• Add the remaining butter to the onions, then stir in the pumpkin purée and cream.
• Season with nutmeg, salt and pepper and let it bubble gently into a smooth sauce.

Melt in the Gruyère

• Lower the heat and stir in the grated Gruyère and Parmesan until melted and glossy.
• Loosen with a splash of pasta water if the sauce is too thick.

Toss the pasta

• Add the drained rigatoni to the pan and toss until every piece is coated in the sauce.

Finish and serve

• Plate the rigatoni and tear the burrata over the top.
• Drape with prosciutto, add a final grating of nutmeg and black pepper and serve immediately.