Hoisin Skirt Steak with Cauliflower

Name: Hoisin Skirt Steak with Cauliflower
Ingredients: 1/4 cup hoisin sauce; 2 tablespoons ketchup; 1 tablespoon rice vinegar; 2 teaspoons finely grated fresh ginger; 2 teaspoons honey; 2 teaspoons sambal oelek or other chili-garlic sauce; 1 1/4 pounds skirt steak, cut into 4 pieces; Kosher salt and freshly ground pepper; 1 small head cauliflower (about 1 1/2 pounds), trimmed and cut into small florets; 8 ounces shiitake mushrooms, trimmed, caps halved; 2 tablespoons plus 1 teaspoon vegetable oil, plus more for the grill; 1 bunch scallions (1 thinly sliced, the rest cut into 1 1/2-inch pieces)