Preheat oven to 400°F.

Place cubed butternut squash into a 9×13-inch baking dish. Drizzle with olive oil and season with salt, pepper, and rosemary. Toss lightly.

Roast for 30 minutes.

While squash is roasting, brown the ground beef in a skillet over medium heat. Drain excess fat.

Add diced onion to the beef and cook until translucent. Stir in minced garlic and cook for 30–60 seconds until fragrant.

Remove squash from oven. Add the beef mixture, instant brown rice, vegetable broth, and heavy cream to the baking dish. Stir well.

Return to oven and bake for about 10 minutes, until rice absorbs most of the liquid.

Sprinkle shredded cheddar evenly over the top.

Bake 5 more minutes, then broil 1–2 minutes if desired until cheese is golden and bubbly.

Let cool slightly before serving.