Preheat your oven to 350°F (175°C). Line an 11×15 baking dish with aluminum foil and coat it lightly with nonstick spray.

Slice the slider rolls in half, keeping the tops and bottoms separate. Place the bottoms evenly into the prepared pan and set the tops aside.

In a small bowl, whisk together the mayonnaise, ketchup, and mustard until smooth.

Heat the olive oil in a large skillet over medium heat. Add the diced onions and cook for about 5-7 minutes until soft and golden brown.

Add the ground beef to the skillet with the onions. Cook until the beef is no longer pink, breaking it apart while it cooks.

Once cooked, drain any excess fat and stir in the dry French onion soup mix and steak seasoning.

Remove the skillet from heat and stir in the mayonnaise mixture until the beef is well coated.

Spread the beef mixture evenly over the bottom half of the slider rolls in the pan.

Layer the top with cheese slices and then place pickle slices on top of the cheese.

Close the sliders with the tops of the rolls, pressing down slightly.

Brush melted butter over the tops and sprinkle with sesame seeds.

Cover the pan tightly with foil and bake for 15-20 minutes until the cheese is melted. Remove from the oven but keep covered for another 5-10 minutes before serving.