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

Soak the cut potatoes in cold water for 15 minutes, then drain and pat completely dry with a towel.

Toss the dried fries with the oil, cornstarch and 1 teaspoon salt until every piece is coated.

Spread the fries in a single layer with space between pieces and bake 35 to 40 minutes, flipping once at 20 minutes, until deep golden and a fry snaps rather than bends.

While the fries bake, brown the ground beef with the onion and garlic in a skillet over medium-high heat, 6 to 8 minutes, breaking it up as it cooks.

Stir in the chili powder and cumin and cook 1 minute until fragrant, then add the kidney beans, tomato sauce and beef broth.

Simmer the chili uncovered 15 minutes, stirring now and then, until it coats the back of a spoon instead of running off it.

Pile the hot fries onto the serving tray and scatter the cheddar over them while they are still hot enough to melt it.

Spoon the chili over the cheesy fries, then top with jalapeno slices, sour cream dollops and green onion just before serving.