Nope, not the same thing.
Here is a basic recipe:
1 quart whole milk
3/4 cup sugar
3 extra large eggs
1 tablespoon vanilla
It is best to use a teflon coated pan for this recipe. Do not double this recipe.
Separate the eggs. Add sugar and flour to the yolks and beat together. Beat the egg whites until stiff peaks form. Add whites to yolks and mix thoroughly. Heat milk to 135 degrees, until steam rises. Pour in egg mixture, stirring constantly. Cook until thickened. It should coat the spoon evenly.
Cool, then add vanilla. Yield: 8 servings.
Some folks spike it with bourbon, but it is delightful just by itself. Especially with a slice of fresh pound cake!
You have to cook this very, very, very slowly. ( I know that's not good grammar, but it gets the point across. )
BTW, the misspelling in the title of the thread was intentional. That is how it is spelled in an 18th century cookbook we have. Another recipe spells it 'Boilt Custard'. Gotta love 18th century English.