Position a rack in the lower third of the oven and preheat to 450°F.

Drizzle 1 1/2 tablespoons of the extra-virgin olive oil onto a large rimmed baking sheet and use a brush or paper towel to coat the surface evenly.

Scrub the 2 medium/larger russet potatoes (about 1 1/4 pounds). Peel them only if you prefer. Cut the potatoes into 1/4-inch-wide sticks.

Place the cut potatoes in a large bowl and cover with very hot water so the potatoes are covered by about 1 inch. Let them soak 10 minutes.

Drain the potatoes and pat them completely dry with a clean kitchen towel or paper towels.

Return the dried potatoes to the rinsed, wiped bowl. Add the remaining 1 1/2 tablespoons extra-virgin olive oil, 1 tablespoon Cajun seasoning, 1 teaspoon garlic powder, 1/2 teaspoon dill weed, and 1/4 teaspoon onion powder. Toss well so the oil and spices coat the fries evenly.

Spread the seasoned potatoes into a single layer on the prepared baking sheet (don’t overcrowd; use two sheets if needed).

Roast on the lower third of the oven at 450°F for 15 to 20 minutes, until the undersides are turning golden. Remove the sheet, gently loosen the fries with a spatula, and flip them in large sections so they rotate and brown more evenly (no need to flip each fry individually). Spread them back into a single layer.

Continue roasting until the fries are golden and as crisp as you like, about 5 to 10 more minutes (total roast time will be roughly 20–30 minutes depending on your oven and desired crispness).

While the fries roast, make the cheese sauce: in a wide saucepan over medium heat, melt 2 tablespoons unsalted butter. Add 1 1/2 tablespoons all-purpose flour and whisk constantly for 1 full minute to form a roux.

Slowly add 1 cup milk (low fat or whole) to the roux, whisking constantly to keep the sauce smooth. Bring the mixture to a gentle boil and continue stirring for 1 minute, until it has thickened slightly.

Reduce the heat to low or remove the pan from direct heat. Slowly stir in 1 cup (4 ounces) freshly grated sharp cheddar cheese a little at a time, stirring until the sauce is smooth and fully combined.

Transfer the roasted fries to a serving plate (or serve directly from the sheet pan). Drizzle the cheese sauce over the fries. If desired, drizzle Ranch dressing and sprinkle with chopped chives or green onions. Serve immediately.