When stuffed with a savory filling, the basic burger takes on a whole new dimension. This recipe includes four different fillings to choose from. Two of them call for caramelizing a yellow onion, which is easy to prepare: In a fry pan over medium heat, warm 1 1/2 Tbs. olive oil. Add the chopped onion, cover and cook, stirring occasionally, until the onion is completely limp, 10 to 15 minutes. Uncover the pan, reduce the heat to medium-low and cook, stirring frequently, until the onion is golden brown and sweet, 35 to 45 minutes. Let cool before using.
Burger filling options (choose one):
4 bacon slices, cooked until crispy and crumbled
2 oz. blue cheese, crumbled
3 oz. feta cheese, crumbled
Zest of 1/2 lemon
1 1/2 tsp. minced fresh oregano
2 oz. feta cheese, crumbled
1 small yellow onion, diced and caramelized
2 oz. Roquefort cheese, crumbled
1 small yellow onion, diced and caramelized
For the burgers:
2 1/4 lb. ground beef
salt & pepper to taste
1 large red onion, sliced 1/4 inch thick
Olive oil as needed
6 hamburger buns
Mayonnaise for serving
Lettuce leaves for serving
6 tomato slices
In a small bowl, stir together the filling ingredients of your choice. Set aside.
Divide the ground beef between 2 bowls. Add 2 1/2 Tbs. of the hamburger seasoning to each bowl. Using your hands, gently mix the ingredients together; do not overmix.
Divide each batch into 3 equal portions and shape each into a ball. Using your thumb, make a deep depression in each ball; do not push all the way through. Spoon about 1 Tbs. of the filling mixture into the depression. Gently shape the meat around the filling, sealing it inside. Using a burger press according to the manufacturer?s instructions, or using your hands, form the balls into patties about 1 inch thick. Transfer the patties to a flexible easy-turn grill basket and set aside.
Put the red onion slices in a shallow bowl and toss with enough olive oil to lightly coat. Arrange on a nonstick grill topper. Set aside.
Prepare a medium-hot fire in a grill.
Place the grill topper on the grill. Cook, turning the onion slices once, until softened and slightly caramelized, 10 to 15 minutes total. Transfer to a plate and cover loosely with aluminum foil.
Place the burgers on the grill and cook, turning once, 5 to 7 minutes per side for medium, or until done to your liking.
Transfer each burger to the bottom half of a bun. Spread mayonnaise on the inside of each top bun. Top each burger with grilled onion slices, lettuce and tomatoes. Serve immediately. Serves 6.
