Pour tomatoes into a strainer that has been fitted over a microwave proof bowl. Using your hands, crush the tomatoes. Press all juices into bowl. Set crushed tomatoes aside. Place bowl with tomato juices in microwave and cook on high until thickened to consistency of ketchup, about 20 to 25 minutes. Add crushed tomatoes to sauce. Cool to room temperature.
Recipe courtesy of Kathleen Daelemans