Didn't take long to locate the recipe. As it turns out, I've had it for about 20 years and I didn't get it from my brother until he'd had it for years before that. Really, really good! Here's the recipe:
PICKLED GREEN TOMATOES
(Makes 3 qts. or 6 pints)
1 onion, thinly sliced
1 red bell pepper, ribs and seeds removed, thinly sliced
3 lbs. green tomatoes (about 9 medium), cut into 1-in. wedges or whole if small
3 to 6 garlic cloves
3 to 6 small red chiles
2 to 3 cups granulated sugar
2 Tbsp. coarse salt
4 cups cider vinegar
4 tsp. mustard seeds
2 tsp. whole cloves
2 tsp. celery seeds
2 tsp. whole allspice
In a large bowl, combine onion, bell pepper and tomatoes and toss to mix as uniformly as possible. Pack into jars.
Place a garlic clove and a red chili in each jar and set aside.
In a large pan, combine remaining ingredients. Bring to a boil over medium-high heat. Stir until sugar dissolves.
Pour mixture into jars - leave ½-inch of head space, seal jars. Process for 10 min. in water bath.
Let pickled tomatoes stand for at least 2 weeks so they have time to meld.