Step 1

Preheat the oven to 425°F and line a rimmed baking sheet with aluminum foil. Spread the fries in an even layer onto the prepared baking sheet and bake until golden-brown and crisp, about 22-25 minutes.

Step 2

Meanwhile, melt the butter in a small saucepan over medium heat. Add the flour and cook, stirring occasionally, until fragrant and smooth, about 1 minute.

Step 3

Whisk in the milk and beer until combined. Reduce the heat to low and simmer, stirring occasionally, until the sauce slightly thickens, about 8-10 minutes. Remove from the heat and whisk in the cheese and mustard until smooth.

Step 4

Top the fries with the cheese sauce, corned beef, sour cream and green onions. Serve and enjoy.