Preheat the oven to 375°F (190°C). Warm the stock in a saucepan; keep it simmering.
In a heavy oven-safe pot or Dutch oven, heat olive oil and butter over medium heat. Add the chopped onion and sauté until translucent and sweet, about 3–4 minutes.
Stir in the minced garlic and cook another 30 seconds until fragrant. Add the Arborio rice, stirring to toast the edges for 2–3 minutes until glossy.
Deglaze with the white wine (if using), letting it simmer away completely and season the pan with a pinch of salt.
Fold in the pumpkin puree, then pour in 1 cup of warm stock. Stir until the liquid is mostly absorbed and the mixture looks creamy but still glossy, about 3–4 minutes.
Pour in the remaining stock, and give the pot a gentle stir. Cover with a tight-fitting lid or foil and transfer to the oven. Bake 18–22 minutes, or until the rice is tender and the dish is creamy but with a kiss of bite.
Carefully remove from the oven. Stir in the crumbled goat cheese (reserve a few crumbles for topping) and the chopped sage. If using Parmesan, fold it in now. Season with salt, pepper, and a pinch of nutmeg to taste.
Return to the oven, uncovered, for 5–8 minutes to finish melding the flavors and slightly dry the top if you prefer a bit more structure. The edges should look glossy and the grains al dente.
Let stand a few minutes, then spoon into bowls. Top with remaining goat cheese, a drizzle of olive oil, and your chosen crunch or greens for texture.
Notes
A cozy one-pan baked risotto featuring pumpkin puree, tangy goat cheese, and sage, baked to creamy perfection without constant stirring.
