1medium eggplant, cut into 1" cubes(about 1 pound)
1teaspoonsalt, plus another 1/2 teaspoon
4medium summer squash, cut into 1" cubes(about 1 pound)
2 - 3bell peppers, or 4 gypsy peppers, halved and seeded (or one 8-ounce jar roasted peppers)
1large yellow onion, diced
2stalks celery (or 1 small bulb fennel), finely diced
4medium tomatoes, diced(3/4 pound, preferably dry-farmed, romas or san marzanos)
3tablespoonscapers (preferably salt-packed), rinsed and drained
1/2cuppitted green olives (such as picholines)
1/2cupred wine vinegar
1/2cupparsley leaves, chopped
Toss the eggplant with 1 teaspoon salt in a colander. Let sweat 20 minutes.
Meanwhile, position racks in the upper and lower thirds of the oven and preheat to 425º. Rub a sheet pan with a bit of olive oil, and place the peppers on it, cut side down. Roast in the oven until collapsing and the skin is browned, about 25 minutes. Let cool. Peel and cut into 1" squares. Set aside.
Meanwhile, toss the zucchini with a tablespoon of the olive oil. Spread in one layer on another sheet pan and roast until tender and browned in places, about 20 minutes.
When the eggplant is done sweating, blot it dry in a kitchen towel. Toss with 1 tablespoon of olive oil. Spread in one layer on another sheet pan and roast until tender and golden, tossing once with a metal spatula, about 30 - 40 minutes.
Meanwhile, heat 2 tablespoons olive oil in a large soup pot or dutch oven. Add the onion and celery and saute over medium heat until tender, 15 to 20 minutes. Add the roasted vegetables, tomatoes and their juices, capers, olives, currants, vinegar, sugar and 1/2 teaspoon salt. Bring to a simmer, then reduce the heat to low and cook, stirring occasionally, until the mixture has reduced to a thick, chunky jam, 20 - 30 minutes. Taste for salt, then remove from the heat and stir in the parsley.
Cool the caponata, then pack it into jars and store in the refrigerator for up to several weeks, or freeze for up to several months.