Pinch the sausage from the tube into bite-sized pieces and place in a single layer in a large skillet over medium-high heat. Cook until no longer pink, making sure to break up the sausage into small crumbles as it cooks.
Sprinkle the flour over the sausage and stir until completely combined.
Cook for a few minutes, then slowly add the milk while stirring constantly.
Cook the gravy, stirring often, until it thickens.
Taste and season with sea salt and freshly cracked pepper, to taste.
Remove from the heat, and the gravy will thicken as it cools.