Cream puffs are great to have on hand because of their many uses. You can make them large or small, and can fill them with custard, ice cream, or seafood. If you want large ones to fill with custard, you will get four puffs per egg; if you want smaller puffs for canapes, plan on twenty puffs to an egg.
Heat butter and water in pan until it boils up. Add flour all at once and mix until it forms a smooth ball. Remove from heat. Put dough into bowl and add the eggs, one at a time, mixing well after each addition. Shape with a spoon on a greased or ungreased cookie sheet. Bake at 400 degrees F for 30 to 40 minutes, or until beads of moisture disappear.
In a bowl mix sugar, cornstarch, eggs, and salt, using a whisk. Pour scalded milk over this mixture and transfer to pan. Cook until thick. Put butter in a bowl and pour the hot mixture over it. Cool and chill.
When ready to use, combine whipped cream and vanilla and mix with the cold custard. Fill puffs. This filling is also good in Boston Cream Pie, or layered with fruit for a pudding.