If you want a more smoother tomato sauce you can add the plum tomatoes to a blender to get the consistency you like before adding them to the slow cooker. My family likes chunky sauce, so I usually use my Mix 'n Chop Kitchen Tool from Pampered Chef to break up the tomatoes before adding the meatballs. I also like to add a little wedge of Parmesan cheese to the slow cooker to give it extra flavor.