Preheat the oven to 300°F (150°C). Line a sheet pan with parchment paper and set aside.

Heat the neutral oil in a cast iron skillet or large skillet over medium-high heat. Once the oil is shimmering, add the sliced bell peppers and onions. Season with Kosher salt and black pepper, to taste. Sauté, stirring often, until the veggies are softened and starting to caramelize on the edges. Transfer the sautéed vegetables to a bowl and set aside.

Add 1 tablespoon (14 grams) of the butter to the hot skillet. Once it's melted, add the steak. Using a spatula, bread the steak apart into bite-sized pieces. Sauté the steak just until it's no longer pink and has some brown bits on the edges. Stir in the garlic powder, Worcestershire sauce, and salt and pepper, to taste.

Reduce the heat to medium-low. Add the peppers and onions back to the pan. Then, add half of the provolone or America cheese. Stir constantly until the filling is melty and well combined. Set aside.

Using a bread knife, cut the Hawaiian rolls in half horizontally, leaving the bottom and top halves intact. Spread 2 Tablespoons (28 grams) of mayo on each cut half. Then, spread the filling evenly over the bottom half of the rolls. Layer the remaining cheese on top of the filling. Place the top half of the rolls over the filling to sandwich everything together.

Melt the remaining 1 tablespoon (14 grams) of unsalted butter. Add the parsley and a pinch of Kosher salt. Brush the parsley butter over the tops of the rolls. Bake for 12-15 minutes, until the filling is warmed through and the tops of the buns are golden-brown. Slice the sliders and enjoy!