This chutney, using underripe tomatoes (not tomatillos), is flavored with garammasala or mild curry powder, but other spices and flavors can be used. It is served cold with meats and curries.
Gently sweat the onion in the olive oil for 20 minutes. Do not allow it to brown.
Peel the tomatoes by plunging them into boiling water, then into cold water, and sliding off the skins. Cut them in half crosswise and squeeze out the seeds. Chop them coarsely.
Add the garam masala to the onions and cook for 1 minute.