Drain the oil from the pan and add a fresh knob of butter. Add the shallots and fry for 1 minute until softened. Stir in the jam, vinegar, sage and a few tablespoons of water. Bring to a simmer and scrape the bottom of the pan with a wooden spoon. Let cook until the sauce is reduced to a syrupy consistency, about 2 to 3 minutes. Add the butter and stir until the sauce is smooth and glossy. Add salt and fresh cracked pepper to taste.