Preheat the oven to 250 F. Wash and prep the tomatoes. I like to remove the green stems and if you are using larger tomatoes, chop them into larger bite sized chunks. Separate and peel all the garlic cloves.
Add the tomatoes, garlic cloves, salt and large bunch of thyme into a dutch oven or over safe pot. Then cover with enough olive oil so that all the tomatoes are just covered.
Cover the pot and place on center rack of the oven for 2 hours.
Remove pot after 2 hours and allow to cool for around 30 minutes to an hour. Remove the thyme bunch before decanting the tomatoes and garlic into jars. Make sure that there is about 1 inch or 2 cm of oil covering all the tomatoes and garlic in each jar to ensure that the tomatoes and garlic are preserved and will not mold or spoil. Store in the fridge.