8 pounds fresh tomatoes (such as plum or San Marzano)
2 large sweet onions, chopped
6 garlic cloves, chopped
1 (6-oz.) can tomato paste
1/4 cup white wine vinegar
2 tablespoons sugar
1 1/2 tablespoons dried Italian seasoning
1 tablespoon kosher salt
1 teaspoon freshly ground black pepper
1/2 cup chopped fresh basil
1 tablespoon fresh thyme leaves
How to Make It
Cut a small "X" in bottom of each tomato. Bring 8 qt. water to a boil in a large stockpot; add tomatoes, and boil 30 to 60 seconds or until peel begins to separate from tomato flesh. Remove with a slotted spoon. Rinse immediately with cold running water, or plunge into ice water to stop the cooking process; drain. Peel tomatoes, and discard skin. Cut tomatoes in half, and gently squeeze to remove seeds. Coarsely chop tomatoes.
Stir together onions, next 7 ingredients, and chopped tomatoes in a 7-qt. slow cooker. Cover and cook on HIGH 4 to 5 hours or until tomatoes have broken down and are very soft. Cool 20 minutes. Stir in basil and thyme.
Process mixture with a handheld blender until smooth, or process mixture, in batches, in a food processor or blender. Season with salt and pepper.
We recommend freezing the sauce in 3-cup portions, which is the amount of sauce found in most bottles of commercial sauce. Put the 3 cups of sauce in a 1-qt. freezer-safe jar or freezer bag to allow for expansion as the sauce freezes.