Everyone loves the spicy-sweet of these burgers.Maple syrup(especially Vermont Maple Syrup)adds a special sweetness to the ketchup and the apple slices.The grilled,glazed apple goes well with the sharp cheese,as well.The pickled onion off-setts the sweet and overall this burger is a delicious package!
Make quick pickled onions:Combine apple cider vinegar,1 tablespoon maple syrup and 1 1/2 teaspoon kosher salt in jar.Shake to combine and add sliced red onion.set aside.This can be done up to 1 week before,or just 1 hour before.
Make burger patties:Combine ground sirloin and ground chuck and form into 4 burgers.Season with kosher salt and fresh ground black pepper.Make Maple Sriracha Ketchup:Combine ketchup,2 tablespoons Sriracha Sauce and 1 tablespoon maple syrup in small bowl.Make glaze for apple slices:Combine 1/4 cup maple syrup with 1 teaspoon lite soy sauce.
Heat grill to medium-high.Brush or spray grill with oil.Grill apple slices that have been brushed with glaze 2 minutes per side.Remove from grill and keep warm.Grill bacon slices until crisp,set aside and keep warm.Grill burgers 5 minutes,flip,grill 3 minutes and top with cheese slices.Toast brioche buns.
To assemble burgers:place mixed greens on bottom roll.Top with burger,grilled apple slices,bacon,pickled onions.Spread top of roll with maple sriracha ketchup and add to burger.