If you want to make the seitan instead of buying it, there are recipes on zaar. This is from an old Vegetarian Times Holiday magazine for Christmas and Thanksgiving.
"This French-inspired stew gets its sumptuous flavor from seitan and vegetables that are first roasted in a fragrant marinade and then stewed with tomatoes and wine."
You can make ahead and add the peas just before serving. They suggest prep the veggies with the marination and then simply put them all in the oven together to cook to help save time.