Filipino Sausage Sliders

Name: Filipino Sausage Sliders
Ingredients: 1 tablespoon plus 1 teaspoon vegetable oil; 3/4 teaspoon annatto seeds (aka achiote seeds); 1 pound lean boneless pork shoulder, coarsely ground by your butcher; 6 ounces pork fatback, coarsely ground by your butcher; 1 tablespoon Worcestershire sauce; 2 teaspoons reduced-sodium soy sauce; 1 1/2 teaspoons kosher salt; 1 1/2 teaspoons granulated sugar; 1/2 teaspoon garlic powder; 1/2 teaspoon Asian chili oil; 1/2 teaspoon ground paprika; 1/2 teaspoon ground black pepper; 12 small soft sweet rolls, such as Hawaiian buns or potato rolls, split open; 2 tablespoons vegetable oil; Garlic mayonnaise and pickled shallots, for serving (see below)