Crunchy French Onion Chicken

Simmer brats in beer, then grill them and top them with caramelized onions, mustard, and pretzel buns for a summery outdoor meal.

2 (12-ounce) lager beers (about 3 cups)
1 medium yellow onion, sliced
3 large garlic cloves, smashed
2 1/2 teaspoons kosher salt
1/2 teaspoon caraway seeds, toasted
1/4 teaspoon black pepper
4 (4-ounce) fresh bratwursts
2 teaspoons canola oil, plus more for grilling
2 tablespoons tap water
2 teaspoons light brown sugar
2 tablespoons spicy brown mustard
4 pretzel sausage buns (such as Pretzilla), split lengthwise 3/4 of the way through and lightly toasted

Stir together beer, onion, garlic, salt, caraway seeds, and pepper in a large saucepan. Nestle bratwursts in beer mixture so they’re completely submerged. Bring to a gentle simmer over medium; cook, stirring occasionally and adjusting heat, as needed, to maintain a gentle simmer, until an instant-read thermometer inserted into center of bratwursts registers 130°F, 3 to 8 minutes. Remove from heat. Using tongs, transfer bratwursts to a plate, and set aside.
Increase heat in saucepan to medium-high, and bring beer mixture to a boil; cook, undisturbed, until onion softens and liquid reduces to about 1/3 cup, 20 to 25 minutes.
Meanwhile, preheat grill to medium-high (400°F to 450°F). Brush bratwursts with oil. Place bratwursts on oiled grates; grill, uncovered, turning occasionally, until charred in spots and an instant-read thermometer inserted into center of bratwursts registers 160°F, 3 to 5 minutes. Transfer to a plate.
Remove saucepan with onion mixture from heat. Remove and discard garlic. Stir in water and brown sugar until sugar dissolves. Spoon 2 tablespoons onion mixture liquid into a small bowl; add mustard, and stir to combine.
Place 1 bratwurst in each bun. Using a slotted spoon, divide onion mixture evenly among buns; discard excess liquid. Drizzle sausages evenly with mustard sauce. Serve.