Bring a large pot of salted water to a rolling boil over high heat. Add the potato gnocchi and cook according to package instructions until they float to the surface. Drain the gnocchi and set aside.

In a medium saucepan, melt 4 tablespoons of butter over medium heat. Whisk in ¼ cup of all-purpose flour, stirring for about 2 minutes until it turns a light golden color, forming a roux.

Gradually pour in 2 cups of whole milk, whisking constantly. Continue to whisk for about 8-10 minutes until the sauce thickens and bubbles gently.

Remove from heat and stir in 2 cups of freshly shredded cheddar cheese until melted. Add 1 teaspoon of kosher salt, ½ teaspoon of freshly ground pepper, ¼ cup of chopped green onion, and ½ teaspoon of garlic powder.

Gently fold the cooked gnocchi into the cheese sauce, ensuring each piece is well-coated.

Preheat your oven to 350°F (175°C). Transfer the gnocchi and cheese mixture into an oven-safe dish. Sprinkle an additional cup of shredded cheddar cheese on top. Bake for about 30 minutes until bubbly and golden brown.