Step 1

In a large bowl, mix together the ground beef, egg, onion, garlic, rosemary, chili powder, salt and pepper until combined

Step 2

Make 4 medium-sized balls and set them on a piece of parchment paper

Step 3

Place 1 pat (about ½ tablespoon) of butter in the middle of each ball

Step 4

Press down firmly on each ball until you have a thin patty

Step 5

Set a cast-iron skillet over medium-high heat

Step 6

Add the oil and once hot, add the patties

Step 7

Cook until browned on the bottom, then as soon as you flip the patties, place the blue cheese on top and cover the skillet to trap the heat

Step 8

Cook until medium-rare or your desired doneness, then transfer to a plate or cutting board

Step 9

Grab the burger buns and toast cut-side down in the same skillet until crispy

Step 10

Remove from the skillet, place a patty between each top and bottom bun and squish down on each burger