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1
Preheat oven to 425 degrees F (220 degrees C).
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2
Spread green, red, and yellow peppers, green beans, white onion, garlic, broccoli, cauliflower, celery, and mushrooms onto several baking sheets and drizzle with olive oil; toss lightly to coat.
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3
Roast the vegetables in the preheated oven until slightly browned and softened, about 30 minutes, stirring occasionally.
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4
While vegetables are roasting, pour ketchup into a large pot over medium heat and stir in tomatoes, white vinegar, balsamic vinegar, salt, and black pepper; bring to a boil. Reduce heat to low and simmer for 5 minutes; stir in roasted vegetables, black olives, green olives, and basil. Simmer until cooked through, about 5 more minutes.
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5
Sterilize jars and lids in boiling water for at least 5 minutes. Pack the roasted vegetable mixture into the sterilized jars, filling the jars to within 1/4 inch of the top. Run a knife or a thin spatula around the insides of the jars after they have been filled to remove any air bubbles. Wipe the rims of the jars with a moist paper towel to remove any food residue. Top with lids and screw on rings.
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6
Place a rack in the bottom of a large stockpot and fill halfway with water. Bring to a boil and lower jars into the boiling water using a holder. Leave a 2-inch space between the jars. Pour in more boiling water if necessary to bring the water level to at least 1 inch above the tops of the jars. Bring the water to a rolling boil, cover the pot, and process for 15 minutes.
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7
Remove the jars from the stockpot and place onto a cloth-covered or wood surface, several inches apart, for 24 hours. Once cool, press the top of each lid with a finger, ensuring that the seal is tight (lid does not move up or down at all). Store in a cool, dark area.
