White BBQ Brisket Sandwiches

• 3 pounds beef brisket
• 1 Spanish onion thinly sliced, large
• 5 cloves garlic minced
• 3 tablespoons olive oil
• 1 1/2 cups tomatoes blended, peeled
• 1/2 cup Worcestershire sauce
• 2 tablespoons apple cider vinegar
• 2 tablespoons Dijon mustard
• 1 tablespoon brown sugar
• 1/2 cup ketchup
• 1 tablespoon chili powder
• 1 chipotle pepper in adobo sauce canned
• salt to taste
• black pepper to taste

FOR THE BUTTERMILK BISCUITS:

• 4 cups all-purpose flour plus more for dusting
• 1/2 tsp baking soda
• 2 tablespoons baking powder
• 2 teaspoons kosher salt
• 12 tablespoons unsalted butter cut into small cubes, very cold
• 2 cups buttermilk

FOR THE PIMENTO CHEESE:

• 1 cream cheese 3-ounce package, room temperature
• 1 cup cheddar cheese sharp, grated
• 1 cup Monterey jack cheese grated
• 1/2 cup mayonnaise
• 1 tsp garlic powder
• 2 to 3 tablespoons Pimentos smashed
• 1 teaspoon onion grated
• salt to taste
• black pepper to taste

FOR THE WHITE BBQ SAUCE:

• 3/4 cup mayonnaise
• 2 tablespoon water
• 2 tablespoon apple cider vinegar
• 1/2 tsp salt
• 2 tsp black pepper coarsely ground
• 1 1/2 tsp mustard
• 1/2 tsp sugar
• 2 garlic minced, clove
• 1 tsp horseradish prepared