Burgers are better with crust. With a smash burger, you get crispy beef on the outside and a napkin-worthy juicy center. To make this burger even better, it's topped with beef bacon and horseradish mayo.
Heat the grill to 400F degrees with a griddle on the grill. Place the beef bacon slices on the griddle and cook for 4-5 minutes per side. Remove to a paper towel-lined plate and set aside.
Clean the griddle. Toast the buns, cut-side-down for about 30 seconds.
Combine the mayonnaise and horseradish. Spread onto the bottom bun. Top with lettuce and onions.
Brush the griddle with oil. Portion the ground beef into four 4-ounce balls, packing loosely.
Place on the heated griddle. Using a large spatula, smash the burger. Use a second spatula to help, if needed. Sprinkle with salt and pepper.
Grill for 2-3 minutes, until the bottom is charred. Flip. Season with salt and pepper. Top with cheese. Continue cooking until the cheese is melted.
Place the burgers on the dressed buns. Spread the top buns with more horseradish mayo. Add to the top and enjoy.