Nona's Favorite Gnocchi Soup

Ingredients

• 2 tablespoons unsalted butter
• 2 tablespoons olive oil
• 2 cloves garlic, minced
• 1 1/2 pounds chicken breast, boneless and skinless, cut into bite-sized pieces
• 1 onion, diced
• 1 1/2 large carrots, diced
• 2 ribs celery, diced
• 1/2 cup all-purpose flour
• 6 cups low-sodium chicken broth
• 1/2 teaspoon dried thyme, plus more, to taste, for garnish
• 1 (16-ounce) package potato gnocchi
• 2 cups half-and-half
• 1 1/2 teaspoons salt
• 1/2 teaspoon black pepper
• 2 cups fresh spinach, chopped