In a large skillet over medium heat, heat olive oil. Once the oil is shimmering, add onion, stirring occasionally until translucent and tender, 6 minutes.
Add ground beef, using a wooden spoon to break up the meat into small crumbles. Season with salt and pepper.
Once half the meat has browned, add garlic, Worcestershire and mustard. Stir until combined, and cook the meat until it is no longer pink at all.
Pile meat onto one hamburger bun, top with pickles, and cover with the other half of the bun. Repeat until you have four sandwiches.
Recipe by Cooking TV Recipes at https://cookingtv-channel.com/roseannes-loose-meat-sandwich/