Grilled Ketchup

This recipe is taken from "Food" by Guy Fieri.  I wish I had some of this left over from making the "Fire-Roasted Shrimp Cocktail" recipe as I would have loved to have made homemade fries to go with it.  This recipe makes 1 1/2 cups of ketchup.  I used white vinegar instead of the apple cider vinegar, not on purpose though...I just thought I had apple cider vinegar in my pantry which I did not. I bought the agave nectar at VitaHealth (a local health food store) as it is not sold at my local supermarket.

1 1/4 pounds Roma tomatoes (about 8), cut in hlaf vertically and seeds removed
1/4 red bell pepper
1/4 small red onion
1 teaspoon olive oil
1/2 teaspoon kosher salt
1/2 teaspoon freshly cracked black pepper
1 Tablespoon apple cider vinegar
2 Tablespoons agave nectar
1 1/2 teaspoons dry mustard
1/2 teaspoon granulated garlic

1.  Preheat the grill to high.  Place the tomatoes skin side up on a baking sheet.  Add the red pepper and onion.  Brush the vegetables very lightly with the olive oil.  Sprinkle with the salt and 1/2 teaspoon of the black pepper.  Turn the tomatoes skin side down and grill all the vegetables until lightly browned, 5 to 8 minutes.  Set aside to cool slightly. 
2.  Combine the vegetables, vinegar, agave nectar, mustard, and granulated garlic in a blender or food processor and process until smooth.  Taste for seasoning.
3.  Let the ketchup sit at room temperature until ready to use.  You can make it ahead and refrigerate to for up to 1 week.