Step 1

Make the aioli - In a blender or food processor, add all the ingredients except for the oils. Turn on and process for about 30 seconds. With the machIne still running, very slowly drizzle in about 1/4 of the oil and stop. Watch mixture and as you see it thicken slightly, very slowly add more of the oil until it is all added.

Step 2

Caramelize the onions - Slice the onions into 1/4 circle slices. Saute in butter on medium for about 45 minutes, stirring often until they become very brown.

Step 3

Make the patties - Place your meat in the freezer for about 30 - 45 minutes before you begin. Slice some of the larger chunks of fat off of the meat and slice into cubes. Place in your food processor (with a little salt) in 2 or 3 batches depending on how large your processor is. Pulse about 15 times to make a nice coarse ground beef. Form the beef into 3 patties.

Step 4

Cook the burgers - In a frying pan with a mix of butter and olive oil, cook the burgers covered and on high heat for around 5 minutes a side. After flipping the first time, add the cheese right away so it melts while the second side cooks.

Step 5

Spread some of the rosemary aioli on both sides of the bun. Place the burger on the bottom bun and top with the caramelized onions. Serve.