Cook the egg noodles in salted boiling water, then drain and cool them under cold water. Pour the noodles into an 8x8 casserole dish and let them stand while you prepare the sauce.

Crush the Ritz crackers in a bowl and set them aside. To prepare the topping, melt the butter and stir in one-third of the crushed crackers.

Preheat the oven to 350°F. Place the chicken on a greased baking sheet and bake for 20 minutes. Once it's cool enough to handle, dice it into ½-inch pieces.

Combine the cream, water, chicken base, and poppy seeds in a saucepan. Bring to a boil, then simmer for 5 minutes. Add the diced chicken to the sauce, heat through, and mix in the remaining Ritz crackers. Turn off the heat and stir in the sour cream until well combined.

Pour the mixture over the egg noodles and top with the crushed crackers and poppy seeds.

Place the casserole in the preheated oven and bake for 20 minutes or until it is bubbly and golden brown.