Peel all the garlic cloves. Reserve one clove for rubbing onto the grilled bread, and cut the rst of the cloves into 1/4 inch thick slices. You should yield about 1/3 to 1/2 cup sliced garlic.
Place the sliced garlic into a small pot with 1/2 cup of olive oil. Bring up the temperature over low heat until garlic starts to bubble gently. Cook at low heat for about 25 minutes or until the garlic has softened and is getting very light golden in color. Do not let the garlic get too dark. Use the weakest burner on your range if necessary to maintain the garlic at a gentle bubble without getting too hot.
While the garlic is gently simmering. Roast the peppers. if the garlic is soft and golden brown before you are finished with the peppers, turn off the heat to the garlic.
To roast the peppers, place each pepper directly over a burner on your stove and turn the heat to high. Cook the peppers directly over the flames so that the skins burn and char. Turn the peppers as they cook until they are completely covered in burnt, charred skin. Don't let the peppers cook for too long after the skin has burnt or you may burn into the flesh. This will not work on an electric stove, you can alternatively use a very hot grill or place the peppers very close to the broiler in your oven.
When each pepper is finished charring on all sides, immediately place it into a heat-safe container and cover it tightly with foil. Once all of the peppers are in the container, keep them covered tightly for at least 15 minutes.
After 15 minutes, open up the container and use a kitchen towel or some paper towels to rub off the charred skins. Don't worry if some specks of charred skin are left behind, this will give a bit of flavor and character to the peppers. Do not be tempted to wash the peppers under running water, you would just be washing away that pleasant smokey flavor.
Remove the seeds and stem from each pepper and cut the pepper into roughly 1.5-inch sections. Slice these sections into 1/8 inch strips.
Thinly slice one shallot.
When the garlic is finished cooking, add the sliced shallot and sliced peppers to the pot with the cooked garlic along with 2 Tsp, kosher salt, and the reserved basil stems.
Simmer everything together over medium-low heat for about 15-20 minutes, stirring occasionally. Discard the basil stems and add the 1.5 Tbsp vinegar to the pot. Turn off the heat and allow the condiment to cool to room temperature. Adjust seasoning with additional salt and vinegar if desired.