Finely dice the mushrooms and slice the onion. Set aside.

In a large skillet, melt a bit of butter over medium heat. Add the sliced onions and diced mushrooms. Season with a pinch of salt and pepper. Sauté for about 5-7 minutes until the onions are translucent and the mushrooms are golden brown. Remove from skillet and set aside.

In the same skillet, add the ground beef. Season it with salt and pepper. Cook over medium heat, breaking it apart with a spatula, until it’s well-browned, about 8-10 minutes. Drain excess fat if necessary.

Once the beef is cooked, stir in the onion and mushroom mixture. Mix well to combine all the flavors.

Evenly distribute the beef mixture into the skillet and top with the Swiss cheese slices. Cover the skillet with a lid and cook for another 1-2 minutes, or until the cheese is melted.

While the cheese melts, prepare the slider buns. Butter the insides and toast them in a separate pan or under the broiler until golden brown.

Scoop a generous amount of the mushroom-beef mixture onto the bottom half of each slider bun. Place the top half of the bun on top, and enjoy your delicious Mushroom Swiss Sliders!