Heat a skillet over medium-high heat. Add the oil and heat through, throw in the sausage and begin to crumble as it cooks with a wooden spoon. Sauté until brown and crispy. Add the onions and garlic and stir to combine. Cook until they've softened. Add the flour and cook for a few minutes. Slowly stream in the whole milk, while you whisk continuously. Lower the flame and cook until the milk has bubbled and thickened. Season with salt and pepper to taste.

Liberally butter the toast and place under the broiler until golden brown. Spoon the sausage gravy over each slice of toast and top with a bit more butter. Enjoy!