Wash the tomatoes and remove the stem end.
Quarter the tomatoes and place them in a roasting pan. Do not overcrowd them!
Add the jalapeno, removing the seeds if you seek a more mild tomato product.
Add the onions, garlic, seasonings, salt and oil.
Toss the ingredients together in the pan. Spread them out.
Roast the tomatoes slowly at 275 degrees or a shorter roast at 375 degrees. (We prefer a slow roast.)
Stir the tomatoes every 20 minutes or so, checking for doneness. Fragrance will be your best indicator -- these things smell great as they are finishing up!
A slow roast may take 4 hours. A quick roast may only take 45 minutes.