Braised Chicken Thighs with Mushrooms and Leeks

large or 3 medium leeks, whites only

kosher salt

Freshly ground black pepper

teaspoon paprika

olive oil spray

pieces bone-in, skin-off chicken thighs, trimmed, about 40 ounces

 tablespoon butter

 ounces white mushrooms, quartered

 tablespoons flour

 cup chicken broth or water with chicken bouillon

sherry