Preheat Oven to 390 °F 

Combine water, butter, sugar, and salt in a medium sized saucepan, and place over medium heat. Bring to a simmer for 2-3 min. 

Turn the heat off and pour all of the flour into the mixture. Using a wooden spoon, combine the flour with the mixture and immediately the mix will thicken and begin to form a dough. Keep mixing until the sides of the pot become clean. And the dough ball has no moisture on the outside*. 

*The residual heat from the pan should be enough to dry the dough, however the pan can be placed back onto the heat in short intervals to further dry the dough. Careful not to burn it! 

Once the dough is dry, place it into a bowl and add 3 eggs. Mix with the wooden spoon until homogenous (keep mixing, it will work, I promise!) The final consistency of the dough should be soft-peaks. 

Use a piping bag to pipe 1” puffs on a cookie sheet and bake for 20 min or until golden brown, do not under any circumstances open the oven door during baking. When golden, turn oven temperature down and open oven door slightly for 5 min before removing. Allow Puffs to cool before filling. 

Cream: 

Using an electric mixer, whip the butter for no less than 8 minutes. The butter should double in size and become white in color. If you find your butter is too warm, simply place bowl in the fridge for 10 min and re-whip. 

Once the butter has been whipped, add in 1/3 of the sweetened condensed milk at a time and whip for no more than 8 seconds each time, for a total of 3 times. Whipping longer may cause the butter and milk to separate. 

It is best to fill the puffs while the cream is fresh so the puff sticks together after it cools. Store in refrigerator, however I don’t think you’ll have any left