Slow Cooker Hometown Brisket

Ingredients

• 3 tablespoons olive oil, divided
• 4 cups onions, sliced
• 4 cloves garlic, minced
• 1 tablespoon brown sugar
• 1 (4-5-pound) fresh beef brisket, cut in half
• 1/3 cup all-purpose flour
• 1 teaspoon salt
• 1 teaspoon coarsely ground pepper
• 1/4 cup balsamic vinegar
• 1 (14.5-ounce) can reduced-sodium beef broth
• 2 tablespoons tomato paste
• 2 teaspoons Italian seasoning
• 1 teaspoon Worcestershire sauce
• 1/2 teaspoon paprika
• 1 tablespoon cornstarch
• 2 tablespoons cold water