Preheat the oven to 180°C/ 375°F. Peel the butternut squash with a peeler and cut into small cubes like shown in the picture.
Add the cut squash to a bowl with the oil and sprinkle a pinch of salt and some fresh cracked black pepper. Toss.
Put the squash on a baking tray lined with parchment paper and set in the oven for about 30 minutes. We want a nice golden colour on the squash with a soft interior. The picture below shows how the squash should look when it's done.
While you are waiting for the squash, get a large pot of water to a boil for the pasta on the stove. Season heavily. It should taste as salty as the sea. Toast the pumpkin seeds for about 5-7 minutes in the oven on a tray. Season with salt when they come out of the oven.
Brown the butter in a small sauce pan and keep warm.
Once the squash is ready, save half of the nicest looking pieces for garnish and set aside. Put the other half in the food processor or blender and purée with the brown butter, and a small squeeze of lemon. Blend until you get the purée as smooth as possible.
Get a medium saucepan on medium heat and add the crushed garlic with the olive oil. Cook slowly until nicely golden being careful not to burn the garlic.
Add the chili flakes to the garlic oil. Discard the garlic cloves and turn off the heat.
Add the pasta to the boiling salted water and cook according to package instructions. Stir the pasta.
Add the squash purée to the garlic/chili oil and one big ladle of pasta cooking water. Cook this over low heat until a nice sauce is formed. It should be pretty soupy as the pasta will soak up a lot of the water from the sauce.
Add the cooked pasta and stir. Add the reserved cooked squash pieces now. Let the pasta cook in the sauce for 1 minute to soak up all that flavour. Add more pasta water if it's too thick.
Plate the pasta and garnish with parmigiano reggiano, toasted pumpkin seeds and some freshly cracked black pepper. Enjoy!