Beer Brats with Roasted Pepper and Garlic Relish and a Celery, Apple, and Fennel Slaw

Brats

• 4 cups beer (not dark)
• 1/4 cup Bavarian mustard
• 2 tablespoons ketchup
• 4 large onions
• 12 uncooked bratwursts
• 6 hard rolls, halved and well buttered
  

Relish

• 2 large heads of garlic, top 1/2 inch cut off
• 5 teaspoons extra-virgin olive oil, divided
• 1/2 cup diced drained roasted red peppers from jar
• 1 tablespoon chopped fresh parsley
• Coarse kosher salt
  

Slaw

• 3 tablespoons extra-virgin olive oil
• 2 1/2 tablespoons apple cider vinegar
• 1 Garlic clove, minced
• 1 1/2 tablespoons coarsely chopped fresh tarragon
• 2 teaspoons fresh lemon juice
• 1/4 teaspoon sugar
• 3 celery stalks, thinly sliced diagonally, plus 1/4 cup loosely packed celery leaves
• 2 small fennel bulbs, thinly sliced crosswise, plus 1 tablespoon chopped fennel fronds
• 1 firm, crisp apple (such as Pink Lady, Gala, or Granny Smith), julienned
• Kosher salt and freshly ground black pepper

Directions

In a large deep heavy skillet stir together beer, mustard, and ketchup.

Cut 1 onion into thick slices and add to beer mixture.

Bring beer mixture to a boil and in it simmer bratwursts, uncovered, turning occasionally, 20 minutes. 

For relish: Preheat oven to 400°F. Place each head of garlic, cut side up, in center of square of foil; drizzle each with 1 teaspoon oil. Enclose garlic in foil. Place packets on oven rack; roast until garlic is tender, about 45 minutes. Open packets; cool 15 minutes. 

Squeeze garlic cloves into small bowl. Mash enough roasted garlic to measure 1/4 cup (reserve remaining garlic for another use). Transfer 1/4 cup mashed garlic to bowl. Mix in 3 teaspoons oil, red peppers, and parsley. Season with coarse salt and pepper. 

Prepare grill. 

Grill bratwursts and buns on an oiled rack set 5 to 6 inches over glowing coals, until bratwursts are cooked through and golden brown about 5 minutes.

Meanwhile for slaw: whisk first 6 ingredients in a medium bowl. Add celery and celery leaves, thinly sliced fennel and chopped fennel fronds, and apple; toss to coat. Season to taste with salt and pepper.

Top each grilled brat with garlic relish, and a drizzle of vinegar