Heat the vegetable stock in a saucepan over medium-high heat, bringing it to a simmer. Reduce the heat to low.
Next, melt the butter in a large skillet over medium heat. Add the onion and squash stirring frequently until the onion is translucent. Stir in the rice and garlic, cooking for another minute or so.
Now add the wine, stirring constantly for another 2 minutes. Add the vegetable stock a half-cup at a time, stirring constantly after each addition until the liquid is mostly absorbed. This is what makes is creamy!
Keep stirring in the stock (a half-cup at a time) until the rice and squash are tender. It’ll take about 20-30 minutes.
Finally, stir in the fresh sage and parmesan cheese, season to taste with salt and pepper. It’s ready to serve!