01 -
Toss cubed butternut squash with 1 tablespoon of olive oil and salt. Spread on a baking sheet and roast in a 430°F oven for 25-30 minutes, stirring halfway through, until tender and caramelized.
02 -
Heat 2 tablespoons of olive oil in a pan over medium-low heat. Add diced garlic and sauté gently, stirring frequently to avoid burning. Add chilli flakes and cook for an additional 1-2 minutes.
03 -
Cook spaghetti in boiling salted water until one minute less than package directions. Drain and set aside.
04 -
Mash half of the roasted butternut squash with a fork. Add both mashed and whole cubes to the garlic and chili oil in the pan, stirring to combine.
05 -
Add drained spaghetti and fresh spinach to the pan, folding them into the squash mixture until the spinach wilts.
06 -
Season with pepper, lemon juice, salt, and additional chili flakes as desired. Drizzle with extra olive oil if preferred. Serve immediately topped with chopped walnuts and lemon zest.