Heat a large Dutch oven or heavy pot on medium-high. Add the oil and onion and cook until softened, 2 minutes. Add the garlic, ginger, curry powder and crushed red pepper, and stir until fragrant, 1 minute.
Add the sweet potatoes and stock. Cover, reduce heat to medium-low and cook for 10 minutes.
Add the peanut butter and coconut milk and stir until the peanut butter is melted and well combined.
Increase heat to medium-high and add the tofu, peas and soy sauce, and cook until warmed through and the sauce is thick, 3 to 5 minutes. Taste and season with salt and pepper.
Serve over rice. Top with cilantro leaves and chopped peanuts, with lime wedges on the side.
