Preheat your oven or air fryer per the fry package instructions.
Spread the frozen fries evenly on a baking sheet so they don’t stick together. Bake until crispy and golden brown.
While fries are baking, melt butter low and slow in your small saucepan or pressure cooker using sauté mode. Add brown sugar, garlic powder, onion powder, chili powder, paprika, salt, and pepper. Stir until fragrant.
Remove fries from oven, toss into a big mixing bowl. Pour the seasoned butter mixture over the fries and mix well.
Pour ranch dressing, flour, and milk into the pressure cooker pot and stir together. Lock the lid, pressure cook on high for 3 minutes. Quick release.
Add shredded cheddar to the pressure cooker and stir until smooth and melty.
Drizzle cheese sauce over fries or serve on the side for dipping.
Enjoy your spicy, creamy, cheesy Louisiana Voodoo Fries.
Store leftovers separately: fries in the fridge or air fryer reheated, cheese sauce in an airtight container.