Wash the tomatoes under cool water and drain.

Sterilize wide-mouth quart canning jars.  Fill the canner with water and heat over high heat to boiling. 

Using a sharp knife, cut a thin slice off the top of the tomato, removing the stem with the slice.

Cut the remainder of the tomato into ½” slices and stack the slices in sterilized wide-mouth quart jars.  Continue slicing tomatoes and filling jars.

Add 1 teaspoon of kosher or pickling salt for each filled quart jar and 2 tablespoons of bottled lemon juice.

Pour boiling water over the tomatoes until covered, leaving a ½” headspace at the top of the jar. Lightly tap the jar or use a knife or spatula to remove air bubbles. If needed, top off with more boiling water to maintain the ½” headspace required.

Wipe the rims of the jars with a clean cloth and apply 2-part canning lids.

Load the filled jars into the canner and bring the water back to a boil.

Once the water is boiling, process the jars for 45 minutes. Ensure the water covers the jars by at least 1”.

After the time has elapsed, turn off the heat and allow the jars to sit in the canner for 5 minutes.

Using a jar lifter, remove the jars from the canner and set them on a towel on the counter, leaving airspace between the jars.  After 12-24 hours, check the seals on the jars, label, and store. Unsealed jars should be refrigerated for immediate use. Sealed jars should be stored in a cool, dark place or pantry and will maintain quality for 12-18 months as long as the seal is intact.