- Melt butter in a large skillet set over medium heat. Add onion, 1 clove garlic and thyme; cook, stirring occasionally for 15 minutes or until softened and starting to caramelize. Add wine and simmer for 10 minutes or until absorbed and onions are very tender. Season with 1/2 tsp (2 mL) salt and 1/4 tsp (1 mL) pepper. Cool slightly.
- Stir breadcrumbs with egg, mustard, Worcestershire sauce, remaining garlic, salt and pepper in large bowl. Gently mix in beef and 1 cup (250 mL) of the cheese. Form into 8 equal patties; press a large thumb-sized indent in centre of each patty for more even cooking.
- Preheat the grill to medium. Grill burgers for 7 to 8 minutes per side or until an instant read thermometer inserted into the side registers 165°F (74°C). During the last 2 to 3 minutes; place a spoonful of the onion mixture on the burgers and top with remaining grated cheese. Cover and grill until melted. Serve on buns topped with tomato and baby arugula.
- Patties can be made and held in the refrigerator for up to 1 day for frozen in an airtight container for up to 2 weeks. To cook burgers from frozen add 3 to 4 minutes to the grill time.
- Maple Cheddar-Cider Burgers: Use ground pork instead of beef. Replace cabernet wine with 3/4 cup (175 mL) hard or fresh cider and 2 tbsp (30 mL) maple syrup; use Black River Maple Cheddar for the cheese. Garnish burgers with grilled apple slices and spinach.