Peel and core tomatoes, discarding seeds and juices. Add to a bowl.
Using your hands or a potato masher, crush the tomatoes into small pieces.
Add olive oil to a saucepan and heat over medium. Add the crushed tomatoes with their juices, salt, Italian seasoning, and pepper. Stir well to coat tomatoes in the seasonings.
Bring to a boil, then simmer for 20-30 minutes, until sauce thickens to your liking. Stir occasionally, using a spatula or spoon to break down tomatoes further.
Remove from heat and purée if desired. Pour into jars and let cool to room temperature, then store in the refrigerator.
Notes
Makes about 2 cups.
To can, divide 1 tablespoon lemon juice equally between 2 half-pint or 4 quarter-pint jars. Pour in sauce, add lids and rings, then process in a boiling water bath for 15 minutes.
To freeze, fill jars or plastic containers, leaving 1/2 inch or more space at the top. Let cool to room temperature, then freeze for up to 3 months.