Step 1: Prepare and Crisp the Potatoes
Wash and slice Russet potatoes into even strips. Soak them in cold water for 30 minutes to remove excess starch, then dry thoroughly with a clean towel.
Toss the dry potato strips with olive oil, salt, pepper, and a dash of paprika.
Arrange them on a baking sheet (ideally on a wire rack) and bake at 425°F (220°C) for 25 to 30 minutes, flipping halfway through until golden brown and crispy.
Step 2: Cook the Seasoned Protein
While the potatoes are baking, brown the ground beef in a skillet over medium-high heat.
Drain the excess fat from the skillet.
Stir in the taco seasoning and water, then let it simmer until the sauce thickens completely.
Step 3: Make the Velvety Cheese Sauce
In a separate saucepan, melt the butter over medium heat, then whisk in the all-purpose flour. Cook for 1 minute.
Slowly whisk in the whole milk and continue stirring constantly until the mixture thickens.
Remove the pan from the heat, add the freshly grated cheddar cheese and a pinch of salt, then stir until completely smooth.
Step 4: Layer and Assemble
Arrange the hot, crispy fries on an oven-safe platter or a cast-iron skillet.
Spoon the warm, seasoned ground beef evenly over the top of the fries.
Drizzle the homemade warm cheese sauce generously over the beef and fries layers.
Step 5: Garnish and Serve
Top the loaded platter with diced tomatoes, sliced jalapeños, black olives, and a heavy dollop of sour cream.
Serve immediately while the fries are hot and crunchy!