​Tomato-glazed mini meatloaves

From Smitten Kitchen. Deb recommends serving these with mashed potatoes.
GLAZE
4 teaspoons vegetable oil
1/4 cup (60 grams) tomato paste
2 tablespoons cider vinegar
2 teaspoons honey
2 teaspoons Worcestershire sauce
2 teaspoons smooth dijon mustard
1/4 teaspoon table salt
​
MEATLOAVES
2 slices sandwich bread
1/2 medium onion, roughly chopped
1 garlic clove, chopped
1 medium stalk celery, roughly chopped
1 medium carrot, roughly chopped
Olive oil, for cooking
1 teaspoon fine sea or table table salt, plus more for vegetables
Freshly ground black pepper
2 pounds ground beef
2 large eggs
1 tablespoon tomato paste
1 teaspoon dijon mustard
1 teaspoon smoked paprika
2 tablespoons Worcestershire sauce
1/4 cup chopped fresh flat-leaf parsley
1/2 cup (120 grams) milk
Make the glaze: Combine glaze ingredients in a small saucepan, and simmer, whisking constantly, for 2 minutes until and glaze is satiny smooth. Set aside.
Prepare the meatloaves: Heat your oven to 350 degrees F. Lightly coat 2 9×13-inch baking dishes with nonstick spray or oil. Tear the bread into chunks and then blend it, in a food processor, into breadcrumbs. Place the breadcrumbs in a large bowl. You should have about 1 cup.

Add the onion, garlic, celery, and carrot to the food processor, and pulse it until they are finely chopped. Heat a large skillet over medium heat. Once the skillet is hot, coat the bottom with olive oil, and heat the oil for a minute; add the finely chopped vegetables. Season with salt and pepper, and cook, stirring frequently, until they begin to brown, about 10 minutes.

Add the vegetables to the large bowl with breadcrumbs, then add the remaining ingredients. Stir the ingredients together with a fork or your hands until evenly blended.

​Form the meatloaf mixture into twelve 3-inch meatballs; each will weigh about 4 ounces. Arrange 6 in each prepared baking pan, evenly. Drizzle or brush each meatball with a teaspoon or so of the tomato glaze you made earlier, and bake until cooked through, about 20 to 25 minutes (an instant-read thermometer inserted into the center of a cooked meatball will register 160 to 165F).
Source: The Smitten Kitchen Cookbook, p. 187