Heat the oil in a medium saucepan over medium heat. Add the tomatoes and allow to cook undisturbed for 3 minutes in order to start to blister their skin and build flavor. Stir and cook undisturbed for an additional 3 minutes.
Once the skins are lightly blistered, stir in the garlic until fragrant, about 1 minute. Then stir in the balsamic vinegar and salt.
Reduce the heat to medium low, cover and cook for 15 minutes until the tomatoes are softened. Stir every 5 or so minutes and then use the back of a spoon to break them (careful as the juices from inside can splatter).
Remove the lid and continue to cook for an additional 15-20 minutes until thickened, stirring often.
Remove from heat and pour into a small jar or glass container. Allow to cool for 30 minutes at room temperature and then place in the refrigerator. The jam continues to thicken as it cools.
Spread on sandwiches, crackers and more.
Notes
LeftoversStore leftovers in an airtight container in the refrigerator for up to 1 week or freeze for up to 3 months.