Gourmet Beef Sliders

Do Ahead

1. Make the rosemary-garlic aioli and refrigerate (covered) for up to 1 day.

Make the Caramelized Onions

1. In a large skillet, melt the butter over medium heat.
2. Add the onions and cook until caramelized and browned, about 35 to 40 minutes. A pinch of salt and pepper and stir. Set aside, but keep warm.

Prep and Cook the Burgers

1. Salt and pepper each side of the patties.
2. Press an indention with your fingers/thumbs in the center of the patty.
3. Heat your grill to medium heat, or heat your skillet to medium heat. Or use your sous vide machine to heat to 145°F. Cook the meat until internal temperature reaches 145°F (for medium).
4. If using your cast-iron skillet, add 1 tablespoon of oil.
5. Once fully heated, add the patties. Cook on one side for about 4 minutes. Then flip. Cook on the other side for about 4 minutes.
6. In the last minute, add the cheese.
7. Meanwhile, slice the buns, butter them, and place under the broiler for about 3 minutes (keep an eye on them! Time varies depending on oven).
8. Remove burgers from heat source.
9. Smear the aioli on each bottom bun. Place the burger on the aioli and then top it with a pile of warm caramelized onions. Place the top bun on the slider and serve at once.