Danish Creamery : Tarragon Butter Roast Chicken with Mustard Pan Sauce

Ingredients

• 3 large shallots, peeled and quartered
• 1 Tablespoon olive oil
• Kosher salt and freshly ground black pepper
• 6 Tablespoon plus 2 Tablespoons Danish Creamery Butter, room temperature
• ½ cup fresh tarragon, finely chopped
• 1 lemon, zested then halved
• 1 (3 to 4 pound) chicken
• 1 head of garlic, halved crosswise
• ½ cup dry white wine
• 1 cup low sodium chicken stock, plus more if needed
• 2 Tablespoons flour
• 2 Tablespoons Dijon mustard