Preheat the oven to 400°F. Line a baking sheet with parchment paper and set aside.
Place a medium saucepan over medium-high heat. Add one cup of water and eight tablespoons of butter. Mix together and bring to a light boil.
Turn the heat down to low. Add all the flour at once and stir vigorously with a wooden spoon until the flour is fully incorporated and the dough forms a smooth ball. Keep mixing as the dough cooks for an additional 1-2 minutes.
Turn off the heat and transfer the dough to a mixing bowl. Beat with an electric hand mixer at medium speed for 2-3 minutes until the dough has slightly cooled.
Add one egg at a time and mix until fully incorporated before adding the next egg. Once all four eggs are mixed in, the dough should be thick and smooth.
Transfer the dough to a pastry bag fitted with a large round tip. Pipe dollops about 1.5 inches wide and one inch high onto the prepared baking sheet. Lightly wet a finger and pat down the peaks.
Bake the puffs for 25-35 minutes, or until they are golden brown and dry. Remove the puffs from the oven and place them on a wire rack to cool completely.
Cream Filling
In a large mixing bowl, combine the heavy cream, powdered sugar, and vanilla. Beat on medium-high speed for 2-3 minutes until the cream is fluffy and soft peaks form. Set aside.
Assembling Cream Puffs
Once the puffs are completely cooled, it's time for assembly. Transfer the cream to a piping bag fitted with a small round tip.
Create an opening in the bottom or side of the cream puff with the pastry tip.
Pipe the cream inside until it pushes back and the puff feels heavy. Refrigerate and then enjoy!