PUFF PASTRY TOPPERS: Follow package directions to thaw the puff pastry and to preheat the oven. Cut puff pastry into squares (I cut each puff pastry sheet 3 times vertically and 3 times horizontally to get 9 squares). Place pastry squares on a lined sheet pan. In a small bowl add the egg and whisk until smooth with a fork. Brush each puff pastry square with egg wash. Bake as directed on the package (we baked 400 degrees F for 12-14 minutes).
VEGGIE PREP: Wash the potatoes and peel if desired (we leave peels on) and cut into small cubes (1/2 inch in size). Finely dice the onion, celery and carrot. Mince the garlic.
VEGGIES: Add 1 tablespoon butter and 1 tablespoon oil to a large pot over medium heat. Add in the onion, celery, and carrot to the pot and sauté, stirring frequently, over medium heat, about 8-10 minutes. Add the garlic in the last 30 seconds.
SEASONINGS AND POTATOES: Add in the thyme, parsley, celery seed, chicken bouillon and salt and pepper to taste (I add 1/4 teaspoon of each). Toss to coat and cook for 1 minute. Add in the diced potatoes and toss to coat, cooking for one more minute.
SIMMER: Cover everything with chicken stock. Heat to boiling and then reduce the heat to medium-low and simmer for about 10-15 minutes or until potatoes are fork tender.
CREAM MIXTURE: Meanwhile, in another pot, melt the butter over medium heat. Gradually add in the flour and whisk until smooth. Cook for one minute over medium heat. Gradually, while whisking constantly, add in 2 cups of milk and whisk until thickened. Again, gradually, while whisking constantly, add in the remaining 1/2 cup heavy cream and stir until thickened. Season cream mixture to taste with salt and pepper (I add another 1/4 teaspoon of each, but add to your preference!)
FINISH THE SOUP: Carefully pour the cream mixture into the vegetable and broth. Stir until thickened, about 5 minutes. Reduce the heat to low and stir in the shredded chicken, frozen peas, and frozen corn to heat through, 1-2 minutes. Reduce the heat to low and stir in the cheese to melt. Remove from heat, taste and adjust seasonings, stir through the freshly chopped parsley, and serve bowls with puff pastry toppers. Enjoy!