Preheat the oven to 400°F. Line two baking sheets with parchment paper. Combine the water, butter, sugar and salt in a medium saucepan. Bring to a boil over medium-high heat.
Remove the pan from the heat and add the flour all at once. Stir vigorously with a wooden spoon until a smooth dough forms.
Return the pan to medium-low heat and cook, stirring constantly, for 1-2 minutes until the dough forms a ball and a thin film develops on the bottom of the pan.
Transfer the dough to the bowl of a stand mixer (preferably stainless steel) fitted with the heavy duty cookie beaters or a paddle attachment. Mix on low speed for 2 minutes to cool slightly.
Add the eggs one at a time, mixing well after each addition. The dough should become smooth, glossy and thick.
Using a large cookie scoop or spoon, portion 12 mounds of dough onto the prepared baking sheets, leaving a few inches between each puff.
Bake, one sheet at a time, for 20 minutes. Without opening the oven door, reduce the temperature to 350°F and continue baking for 15-20 minutes more until deeply golden brown and crisp.
Turn off the oven, crack the door open slightly and let the puffs sit for 10 minutes. Transfer to a wire rack and cool completely.
Make the Filling: Beat the cream, powdered sugar and vanilla together until medium peaks form.
Slice the cooled cream puffs horizontally using a serrated knife. Arrange strawberries over the bottom half of the puff and spoon or pipe whipped cream on top. Replace the tops. Dust generously with powdered sugar and serve immediately.
Notes
Be sure not to open the oven door while the puffs are baking. It can cause them to collapse.
You can bake both baking sheets at the same time, but because you can't open the oven door while they are baking, you can't rotate the pans so the top batch will be darker in color than the bottom batch.
Fill the puffs just before serving for the best texture.
To store puffs: Once they have completely cooled, store the unfilled puffs in an airtight container at room temperature for up to 24 hours or freeze for up to 3 months.