Preheat oven to 400°F (200°C). Toss squash cubes with 1 tbsp olive oil, salt, and pepper. Roast 25 minutes.
Heat remaining oil in skillet. Sauté onion and garlic until translucent.
Stir in arborio rice, coating grains in oil for 2 minutes.
Pour in wine, stirring until absorbed (skip if you must).
Add warm broth, one ladle at a time, stirring until liquid is mostly absorbed before adding more.
When rice is tender and creamy (about 25 minutes), fold in roasted squash gently.
Season to taste and garnish with fresh herbs.