Heat a remaining 1 tablespoon oil in a middle saucepan over medium-high heat until shimmering. Add a sausage as well as cook, violation it up with a wooden spoon, until lightly browned, about 4 minutes. Add a onion reduction as well as cook, stirring occasionally, until a dampness has evaporated from a pan as well as a onions are soft, about 5 minutes. Stir in a marinara sauce, oregano, red peppers flakes, 1/4 crater water, 1/2 teaspoon salt as well as several grinds of black pepper. Bring to a simmer, revoke a heat to middle low as well as cook, uncovered, stirring often, until thick, about fifteen minutes.