Crispy roast chicken with a quick pan sauce

Name: Crispy roast chicken with a quick pan sauce
Ingredients: 3 tablespoons kosher salt; 1 bay leaf; 1 tablespoon whole black peppercorns; 1 3 - 3.5 pound chicken (mine was 3.28), quartered with wing tips removed.; 1 large onion, halved, peeled, and sliced into 1/3 inch slices; 1 fennel bulb, trimmed, core removed, and sliced into 1/4 inch slices; 4 cloves of garlic, unpeeled; 1/3 cup white wine; 1/4 cup chicken broth; olive oil; herbs de provence; 1/2 teaspoon dijon mustard; 1 tablespoon butter