Holiday Brisket

lbs brisket, first or second cut ((do not trim fat - especially if it's grass fed))

extra virgin olive oil, divided

large brown onions, peeled and sliced

carrots, peeled and sliced

celery, peeled and sliced

tomatoes - whole, diced, or crushed ((1 large can))

peeled whole garlic cloves

brown sugar

vinegar ((I like apple cider vinegar, but white vinegar works too))

beef or chicken broth, divided

Salt and pepper