Easy Homemade Turkey Gravy

Ingredients

• 2 4, skin-on, bone-in turkey thighs
• 1 teaspoon salt, plus
• 1 teaspoon black pepper
• 1 teaspoon garlic powder
• 1 teaspoon onion powder
• 2 tablespoons flour
• 1 tablespoon olive oil
• 2 tablespoons butter
• 4 to 5 cups turkey or chicken stock
• 3 celery stalks, roughly chopped
• 1/2 onion, roughly chopped
• 3 garlic cloves, smashed
• 2 bay leaves
• 1 tablespoon Better than Bouillon Turkey Base, optional
• cornstarch slurry