Ode to Onion Burger with Boursin & Arugula
White Castle burgers with their spicy mustard and minced onion are the inspiration for this recipe. My family affectionately refers to White Castles as “Whitey One-Bites’, and though we don’t ever order ours with cheese, I have included Boursin cheese here, along with arugula and onion “marmalade”.
1-1/2 pounds 85/15 ground beef
2 medium yellow onions
4 tablespoons horseradish mustard
1 tablespoon butter
1/2 teaspoon salt
1/4 teaspoon freshly-ground black pepper
1 tablespoon balsamic vinegar
1 – 5.2 ounce package Boursin Cheese (Garlic & Herb)
2 cups baby arugula, washed and spun dry
6 onion hamburger buns, split
1. Mince one of the onions and thinly slice the other.
2. Mix the beef with the minced onion and 2 tablespoons of the mustard until just combined. Form 6 patties.
3. Prepare a chimney for a charcoal grill.
4. When the coals are hot, melt the butter in a saute pan placed over the hottest part of the grill, 4 inches from the heat. Add the sliced onions, salt and pepper, stirring to coat. Cook for 5 minutes stirring occasionally.
4. Move the pan with the onions to a side of the grill where it will still receive heat. Place the patties on the hot part of the grill, cooking for 5 minutes. Flip the burgers and cook for 5 more minutes, stirring the onions occasionally.
5. When flipping the burgers, put the bun halves on a higher rack or to a cooler side of the grill to toast.
6. Remove the buns and burgers from the grill, and move the pan of onions back to the hottest section of the grill. (Onions should be soft and golden at this point.)
7. Add the balsamic vinegar to the onions, stirring to coat, and cooking 5 minutes more until vinegar is absorbed and onions have begun to caramelize.
8. While the onions and vinegar cook, divide the Boursin among the 6 bun bottoms, spreading evenly. Divide and spread the remaining 2 tablespoons of mustard among the bun tops.
9. Place a burger onto each bun bottom (on top of the Boursin), then top the burger with the onion “marmalade”, the arugula, and the bun top. Dive in!