Add water and a bit of salt to a large pot and place over high heat to cook the gnocchi. While it's heating, prepare the cheese sauce.

Preheat oven to 350F (regular bake setting/not fan assisted) with rack in the centre of the oven. Oil or butter an 8-inch square baking dish, an 8-inch cast-iron skillet or individual baking dishes.

For the cheese sauce: In a large saucepan, melt the butter over medium heat. Whisk in the flour and continue to whisk and cook for about 2 minutes.

Very slowly add the milk, a little at a time, whisking constantly. Once all the milk has been added, cook, stirring frequently until the sauce thickens, about 8-10 minutes. (Don't rush this step. The mixture will not be thick, but will noticeably thicken after 8-10 minutes of cooking).

Remove the saucepan from the heat. Add the cheese, salt, pepper, green onion and garlic powder. Stir until the cheese is melted and all the ingredients are incorporated, about 3 minutes. (If the cheese isn't melted completely after about 3 minutes, you can put the pan back on low heat and stir until it is melted). Stir in sour cream *or alternately, leave out of the sauce and serve on top with the garnishes.

Add gnocchi to boiling, salted water and cook according to the package instructions. Don't overcook. Drain gnocchi well and stir gnocchi into cheese sauce until well coated. Transfer to an oven-safe baking dish or individual dishes. Top with additional shredded cheddar cheese.

*Can be prepared up to this point, covered and refrigerated until ready to bake. If baking cold from the refrigerator, allow a few extra minutes in the oven to warm through.

Bake in preheated oven for 30 minutes. Serve warm garnished with diced green onion, cooked bacon crumbles and optionally, a dollop of sour cream.