1 large carrot, finely chopped
4 cloves garlic, chopped, 1/2 teaspoon salt, 1/2 teaspoon ground black pepper, 1/2 teaspoon ground black pepper
1 large tomato, coarsely chopped
Reduce heat to medium-low and place vegetables and cook in under-casserole. Remove vegetable from oven; cool, cut into bite-size pieces.
Steep mustard seed in an open bowl and pour in crushed tomatoes and dry balsamic vinegar. Bring to a boil while still warm. Reduce heat to low and simmer, stirring occasionally, for 15 to 20 minutes. Stir in squash.