Cool completely.
Take a 1/2 cup of heavy whipping cream, whipping it until soft peaks form and gently folding the whipped cream into the custard mixture.
Pre-heat oven to 400 degrees. In a sauce pan bring butter, water and salt to a boil. Add 1 cup of flour to the boiling liquid all at once and stir until a ball forms.
Take pan off heat and let mixture cool for 5 minutes. After the flour mixture has cooled, start beating in the eggs, one at a time. Mixing well after each egg.