Bangers and Mash with Guinness-Onion Gravy

Steps

1. 1Combine potatoes and 1 tablespoon salt in large saucepan and add water to cover by 1 inch. Bring to boil over high heat. Reduce heat to medium and simmer until potatoes are fork-tender, 15 to 20 minutes. Drain potatoes and return to saucepan. Add half-and-half and 5 tablespoons butter. Using potato masher, mash potatoes in saucepan until smooth. Season with salt and pepper to taste.
2. 2Meanwhile, melt 1 tablespoon butter in 12-inch nonstick skillet over medium heat. Add bratwursts and cook until well browned on 2 sides, about 5 minutes. Transfer bratwursts to plate. Wipe skillet clean with paper towels.
3. 3Add 2 tablespoons butter, onion, and salt to now-empty skillet and cook until onion is softened and lightly browned, 4 to 6 minutes. Stir in flour and cook for 1 minute. Whisk in broth, Guinness, mustard, and pepper. Add bratwursts and bring to simmer. Reduce heat to medium-low; cover; and cook until bratwursts register 160 degrees, 10 to 12 minutes. Transfer bratwursts to serving platter. Off heat, stir remaining 2 tablespoons butter into onion mixture. Serve bratwurst with mashed potatoes and spoon onion mixture over top.