Place large dutch oven over medium heat. Add butter and sautee onion and carrot 4-5 minutes or until onion starts to turn translucent and softens. Add in garlic and cook another 1 minute until fragrant.
Sprinkle flour over the veggies and stir in and cook 1 minute. Whisk in chicken stock, bouillon paste, milk and salt & pepper. Reduce heat to low. Once you add the milk, you don't want to boil the soup.
Stir in shredded chicken and cook on low until carrots are tender, 10 minutes. Add in gnocchi and cook another 3 minutes or until they are cooked. Right before serving, stir in heavy cream and chopped spinach. Taste and adjust seasonings as needed (will most likely need salt). Divide into bowls and serve.