Preheat oven to 400 F. Line 2 baking sheets with parchment paper.

Peel butternut squash and chop into 1-inch cubes.

Place butternut squash in a large bowl and add olive oil, cinnamon and salt. Use a wooden spoon to mix well, until the squash is evenly covered with olive oil and cinnamon.

Place the squash on a baking sheet and bake in the preheated oven for 30-35 minutes, until fork tender.

While squash is in the oven, roughly chop the walnuts.

Place the walnuts in a bowl and add maple syrup, cinnamon and salt. Toss to combine until the walnuts are evenly covered.

Spread the walnuts in a single layer on a baking sheet and bake in the preheated oven for 15 minutes, tossing them halfway through (I recommend adding to the oven with the squash when there are about 15 minutes left).

Remove squash and walnuts from the oven. Let walnuts cool for about 5 minutes to harden.

Add squash and walnuts to a large serving bowl and garnish with sage. Serve immediately.