1. Heat olive oil in a large skillet over medium-high heat. Add seitan and cook, stirring, until seitan is browned and caramelized on all sides. Reduce heat and add shallots, carrots, and garlic; cook, stirring, for 3 minutes. Stir in tomato paste and cook, stirring, for 2 minutes.

2. Transfer seitan mixture to a large saucepan; add wine and enough stock to just cover seitan mixture. Add parsley, bay leaves, thyme, and pearl onions; cover and bring to a simmer until vegetables are tender. Transfer seitan, carrots, and onions to a large serving bowl; set aside and keep warm.

3. In a small bowl, mix together flour and margarine. Add flour mixture to saucepan, stirring until well combined. Let sauce simmer, uncovered, until it reaches a gravy-like consistency. Remove bay leaf and season with salt and pepper.

4. Pour sauce over seitan in serving bowl; garnish with mushroom "bacon" topping and parsley. Serve.