I made eggplant parm with a homemade tomato sauce(olive oil, whole tomatoes garlic and onion cooked then whizzed with immersion blender). The sauce was good and the eggplant parm was good but there was a watery bit in the bottom of the pan. This also happens when making tomato mozzarella lasagna. It almost seems like the sauce has broken, how do I keep it 'emulsified'?