1. Prepare the stew. Whisk beer, wholegrain mustard, vinegar, 1 tsp. thyme, and 1/8 tsp. cayenne together in a small bowl.
2. Heat oil in a large stockpot over medium-high heat. Add kielbasa and cook until lightly browned all over, about 3 minutes.Transfer to a plate.
3. Add beer mixture to pot and bring to a simmer over medium-high heat. Stir in cabbage, potatoes, carrots, onion, garlic, pepper, and salt, if using. Nestle kielbasa into cabbage, cover, and cook over medium-high heat until cabbage is tender and potatoes and carrots are cooked through, about 20 minutes.
4. While cabbage cooks, prepare mustard sauce. In a small bowl, whisk together all sauce ingredients. Reserve.
5. Remove kielbasa from pot and slice diagonally into 1/2-inch-thick pieces.Transfer cabbage to a serving dish and layer kielbasa on top. Serve immediately, with mustard sauce on the side.
Source: Hannaford fresh Magazine, January - February 2010