In a medium pot, add water, milk, butter, sugar, and salt. Bring to a gentle boil. Once the butter is fully melted, add the flour all at once and stir quickly with a wooden spoon until it turns into a smooth ball. Keep stirring on low heat for about 1-2 minutes to dry it out.

Move the dough to a bowl and let cool for a few minutes. Add eggs one at a time, mixing well after each addition until the final dough is smooth, glossy, and falls from the spoon in a thick ribbon.

Spoon the dough into a piping bag and pipe logs onto a lined baking sheet, about 4 inches long. Bake until puffed and deep golden brown. Turn off the oven, crack the door, and let sit for 10 minutes.

Heat milk until steaming. In a bowl, whisk egg yolks, sugar, and cornstarch until smooth. Gradually add hot milk while whisking, then return to the pot. Stir on medium heat until thickened. Remove from heat and stir in butter and vanilla. Chill until cold.

Once shells are cool, poke holes in the ends or slice them. Pipe in the pastry cream. For the glaze, heat cream until hot, pour over chopped chocolate, wait a minute, then stir until smooth. Dip tops and let set.