Heat olive oil in a skillet over medium-low heat.

Add onions and garlic, and cook, stirring until lightly browned.

Increase the heat to medium, and add the green pepper and seitan to the pan, stirring to coat the seitan evenly.

Season with salt and pepper. Add the water, reduce heat to low, cover, and simmer for 35 minutes in order for the seitan to absorb the flavors.

Cook, stirring until thickened, and serve immediately.