Heat a grill to medium heat (350-400°F) and lightly oil the grates.
Using a fork, poke holes into the eggplant skin in several areas and set it on the grill along with the red peppers.
Grill the eggplant and peppers about 20 minutes, turning occasionally, until the red pepper skins char and puff up and the eggplant softens and wrinkles all over. Remove red peppers and turn off heat. Leave eggplant for another 5 minutes on grill.
Place peppers in a bowl and cover them with a towel to let them steam. When cooled, peel off the charred skins and remove the seeds and stems. Cut off the stem from the eggplant, slice it lengthwise and scoop out the eggplant flesh. Discard the skin and stem.
Add the roasted peppers and eggplant to a food processor along with the garlic, oil, vinegar, salt and pepper. Process it to a smoothe texture.
Scrape the mixture into a saucepan and simmer for 20 minutes to cook the garlic, mellow the vinegar and to develop flavors. This is a slightly sweet, bright red pepper flavored sauce. If you'd like it spicy, add a 1/4 teaspoon of ground cayenne powder at this point. Season with salt.
Serve with grilled meats, flatbreads, croutons or crackers of choice. Great as a vegetable dip as well.
This makes about 2 1/2 cups. Store in an airtight container, lasts 5-7 days.