Preheat oven to 425°F (220°C). Toss the 1.5 lbs (680g) cut russet potatoes with 3 tbsp olive oil, 1 tsp garlic powder, 1 tsp onion powder, 1 tsp smoked paprika, 1 tsp fine salt, and 0.5 tsp black pepper. Spread in a single layer on a baking sheet and roast for 25 to 30 minutes, flipping once at 15 minutes, until the edges are deep golden and crisp.

Melt 2 tbsp unsalted butter in a medium saucepan over medium heat. Add 2 tbsp all-purpose flour and stir for 1 minute until the mixture looks like pale sand.

Pour in 1 cup (240ml) whole milk slowly, whisking constantly, then add 0.5 cup (120ml) lager beer and whisk until smooth and beginning to thicken, about 2 to 3 minutes.

Reduce heat to low. Add 2 cups (200g) grated sharp cheddar one handful at a time, stirring between additions. Stir in 1 tsp Dijon mustard, 0.5 tsp Worcestershire sauce, and 0.25 tsp cayenne. Season with salt to taste and stir until smooth, about 3 to 4 minutes.

Pile the fries on a plate, ladle the warm cheese sauce into a bowl alongside, and finish with a pinch of smoked paprika over the sauce and cracked black pepper over the fries.