Prepare and gather the ingredients for the choux pastry. Using the second listed amount of soy milk, mix it together with the Just Egg. Set aside for later.
Combine the water, soy milk, vanilla extract, sugar, and butter in a small saucepan on medium heat. Mix it with a rubber spatula until the butter dissolves and then leave it for a few minutes until it starts to simmer.
Once the liquid ingredients begin to simmer, carefully add in all the flour. Turn the heat to low. Continue to mix until the flour is incorporated and no white flour spots remain. The mix will thicken into a dough and almost form a ball. It should come off the sides of the pan easily. This shouldn’t take more than about 3 minutes.
Scoop the dough out of the pan and into a mixing bowl or the bowl of a stand mixer. Avoid using a plastic bowl as the dough will be hot. Smash the dough down and flatten it to help release the heat. Leave it to cool for a few minutes. Alternatively, you can mix the dough over some ice or some ice packs to help it cool more quickly. You can also mix the dough for a few minutes in a stand mixer with a paddle attachment.
Once your dough is just barely warm or room temperature, add in the Just Egg mixture a few tablespoons at a time. The amount is up to you. We’re just trying to avoid mixing a ball of dough sitting in egg soup—that would be more difficult to mix! Mix it with the rubber spatula and allow it to fully incorporate in between each addition. The final consistency should just barely run off the spatula and look pipe-able. Add more soy milk a tablespoon at a time if your mixture is still too thick.
Preheat the oven to 400°F.
Scoop the choux mixture into a piping bag with a 1/2 inch opening or smooth tip.
TIP: If using reusable piping bags, you can close the open end of the bag by the tip with a pastry bag tie.
Then place the piping bag into a tall glass to help you fill it more easily.
Next, tie the back end of the bag.