Combine water, milk, butter, sugar and salt in a medium pot. Bring to a boil over medium heat.
Add the flour and stir with a wooden spoon until the mixture comes together and forms a dough. Continue to stir the dough until it begins to dry and you see a film start to form at the bottom of the pot as the result of the dough sticking, 1 to 2 minutes.
Transfer the dough to a stand mixer fitted with a paddle. Add the eggs one at a time on med low setting on the mixer until all the eggs have been incorporated.
Transfer mixture to a piping bag and pipe onto a parchment lined baking pan. Cook in the combi oven. Remove from oven and let cool. Then fill with pastry cream and dip in ganache.