Wash and dry all produce. Preheat oven to 425 degrees. Halve, peel, and thinly slice onion. Slice tomato into rounds. Halve brioche buns. Form beef into two 1-inch thick patties. Season on all sides with salt and pepper.

Toss broccoli on a baking sheet with a drizzle of olive oil and a pinch of salt and pepper. Roast until slightly crispy, about 15 minutes.

Heat a drizzle of olive oil in a large pan over medium-high heat. Add onions and cook, stirring often, until soft, 5-6 minutes. Add 1 TBSP sherry vinegar and 1 tsp sugar, and simmer until liquid is nearly evaporated. Season with salt and pepper. Transfer to a bowl and set aside.

Line another baking sheet with parchment paper. (TIP: If you don’t have parchment, that’s ok! Just remove crispy frico from baking sheet while still hot.) Place cheese in two even piles on baking sheet. Bake until melted in middle and crispy at the edges, 5-7 minutes.

Meanwhile, heat a drizzle of olive oil in same large pan over high heat. Add burgers and cook to desired doneness, 3-6 minutes per side. After you flip the burgers, place buns in oven to toast 3-4 minutes.

Place burgers, caramelized onion jam, tomato slices, ketchup, and a cheddar frico inside each bun. Serve with crispy broccoli on the side.