Prepare the rice: Cook the brown rice according to package instructions.

Season the shrimp: Pat shrimp dry, then season with salt and pepper and lightly dredge in flour.

Sauté shrimp: In a large sauté pan, heat 2 tablespoons of vegetable oil over medium-high heat. Add the shrimp and cook just until lightly golden, about 1–2 minutes per side. Remove shrimp and set aside.

Cook vegetables: In the same pan, add the remaining oil (if needed). Sauté the onion, mushrooms, and bell pepper until softened and fragrant, about 5 minutes. Season with salt and pepper.

Add tomato paste: Stir in the tomato paste and cook for 2 minutes to remove the raw flavor.

Deglaze and simmer: Turn up the heat, pour in the white wine, and let it reduce for 2–3 minutes. Add the broth and chopped tomatoes and bring to a simmer.

Finish shrimp: Return the shrimp to the pan, stir in any accumulated juices, and simmer for 2–3 minutes to heat through. Turn off the heat and stir in the butter.

Serve: Spoon over cooked brown rice and serve immediately.