In a large pot, combine the butter and water.
Heat over medium high heat until it reaches a rolling boil.
Remove from the heat and add in the 1 cup of flour all at one time and salt. Stir until a thick paste forms.
Add the eggs, one egg at a time, mixing thoroughly in-between each addition with a wooden spoon or heavy duty silicone spatula.
Mix until you have a smooth pastry batter.
Allow the batter to rest for 15 minutes.
While the batter is resting, preheat your oven to 425° F.
After the batter has rested, add the batter to a large piping bag.
Pipe 4 inch long lines on a silicone lined cookie sheet. Try to use even pressure while holding the piping bag at an angle, this will help your eclairs to be more uniform in size.
Bake the eclairs at 425° F for 10 minutes and then without removing the eclairs form the oven, reduce the heat to 350° F and bake for an additional 25-30 minutes, or until they are golden brown.
Immediately after they come out of the oven, use a skewer to poke a hole through the pastry lengthwise to help the steam escape from the inside so they don’t collapse while cooling.
Once the pastries are cool, make the filling.