Preheat an oven to 425 degrees and line a baking sheet with parchment paper.
In a bowl mix together the flour, salt, and arrowroot powder. Set aside.
Bring the water and Dairy Free butter to a boil. Once boiling pour in the flour mixture, continually stirring with a wooden spoon.
When the dough pulls away from the pot and starts to form a ball, place the ball into a mixing bowl with your mixer on medium speed.
With the mixer running, add one egg at a time, allowing it to fully incorporate before adding the next.
Once all of the eggs have been fully incorporated transfer your dough to a piping bag fitted with a large round tip.
Pipe out 5" strips onto the parchment paper.
Bake at 425 for 15 minutes. Reduce heat to 350. Do not open the oven.
Bake for an additional 25 minutes.
Remove the cookie sheet from the oven. Cut a slit on top of each pastry shell and place back in the oven for an additional 5 minutes.
Remove from the oven and allow to cool completely on a wire wrack.
Slice the pastry shell in half and then scoop out the interior to make room for the pastry cream.
Vanilla Bean Pastry Cream
Add the oat milk and vanilla beans to a pot and place over medium heat. Bring to a boil. Once boiling reduce the heat to low.
In a separate bowl mix together the eggs, sugar, salt, and cornstarch.
Add one cup or ladle full of the hot oat milk mixture to the egg mixture, continually stirring, to temper the eggs.
Pour the warm egg mixture into the hot oat milk mixture, constantly stirring.
Whisking constantly turn the heat up to medium/low. Continue to whisk until the mixture thickens, and then become thick. It should firmly hug the back of a wood spoon.
Pour into an air tight container and allow to refrigerate until it is fully cooled.
Once cooled pipe into the hollowed out pastry shells.
Chocolate Topping
Gently melt the chocolate. Stir in the tiramisu flavoring.