Crisp Branzino with Spinach

Name: Crisp Branzino with Spinach
Ingredients: 1 stick cold unsalted butter, cut into tablespoons; 1 large shallot, minced; 2 tablespoons chicken stock or low-sodium broth; 2 tablespoons fresh lemon juice; 2 tablespoons drained capers, rinsed and coarsely chopped; 1 tablespoon Worcestershire sauce; 3 tablespoons minced chives; 1/4 cup plus 1 tablespoon extra-virgin olive oi; Two 1 1/4-pound whole branzino, cleaned and scaled; Salt; 4 garlic cloves—2 chopped, 2 thinly sliced; 1 teaspoon thyme leaves, chopped; 1/2 pound baby spinach