Heat the oven to 425°F and line a sheet pan with parchment paper.

Soak the potatoes in cold water 15 minutes, drain, and pat completely dry.

Toss with oil, cornstarch and salt, spread in a single layer, and bake 35 to 40 minutes, flipping once, until deep golden and crisp.

While the fries bake, melt the butter in a large skillet over medium-high heat and add the onion and bell pepper.

Cook the onion and pepper 6 to 8 minutes, stirring occasionally, until softened and lightly browned at the edges.

Push the vegetables to one side, add the sliced steak to the other, and cook 3 to 4 minutes, stirring, until no longer pink.

Season with black pepper and Worcestershire sauce, then stir the steak and vegetables together.

Pile the hot fries onto a platter, top with the steak and pepper mixture, and scatter the torn provolone over the top while everything is still hot enough to melt it.

Finish with chopped parsley and serve right away.