Big Burger with Herbs

3 Tbsp. butter
½ cup (100 g) sugar
2 large onions, sliced
3 Tbsp. (45 ml) cider vinegar
2 Tbsp. fresh oregano, chopped
2 Tbsp. fresh thyme, chopped
1 Tbsp. chives, chopped
1 lb (450 g) ground beef
1 lb (450 g) ground pork
2 eggs
1 tsp. paprika
½ cup (100 g) Panko breadcrumbs
Salt and pepper
2 Tbsp. olive oil
4 burger buns
½ cup (100 g) mustard

1. Preheat oven to 350°F.
2. In a bowl, mix chopped herbs, ground beef, ground pork, eggs, paprika and panko breadcrumbs. Add salt and pepper; mix well. Form thick patties with preparation.
3. In a saucepan, heat olive oil. Add patties and cook 4 minutes on each side. Transfer to an oven dish and bake 20 minutes in oven or until meat is done to taste.
4. Spread mustard on buns. Add some cooked onions. Place a big burger patty on each bun. Top with some more cooked onions and serve.