Sheet Pan Honey Mustard Chicken Thighs w/ Potatoes & Carrots

olive oil, plus more for greasing the pan

Dijon mustard

honey

chicken thighs (bone-in or boneless, with or without skin)

sea or kosher salt and fresh black pepper

russet potatoes, peeled, cut in half lengthwise & cut into thick half moons

carrots, cut in half lengthwise then cut again into 1 to 2-inch long spears

small red onions, cut into 8 wedges each through the root