Preheat the oven to 425 degrees F and line baking sheets with parchment paper.

Place the water, butter, sugar, and salt in a small pot and cook over medium-high heat until the butter is completely melted and the mixture is simmering.

Add in the flour all at once, and continue to cook, whisking, for about 5 minutes, or until the dough gathers itself into a ball and a film begins to form on the bottom of the pot.

Transfer the mixture to a mixing bowl, and beat on medium speed.

Drop in the eggs, one at a time, while continuing to beat. Allow each egg to become fully incorporated before adding the next.

Pipe or spoon the dough in 1 1/2-inch balls onto the prepared baking sheets, allowing about 3 inches in between each puff.

Bake for 35 to 45 minutes, or until puffed, golden brown, hollow, dry, and light.

Allow the pastries to cool completely, then slice open horizontally.

To make the cream puff filling, place the cream cheese and powdered sugar in a large bowl and beat on medium speed until smooth.

Turn the mixer down to medium-low speed and pour the heavy cream down the side of the bowl in a very slow and steady stream, stopping every now and then to scrape the bottom and sides of the bowl with a silicone spatula.

When all the cream has been added, turn the mixer up to medium-high and whip until the filling holds stiff peaks.

Fold in the vanilla.

Sandwich the cream puff filling into the sliced pastries and dust with powdered sugar.