Take puff pastry out to thaw according to package directions.

Meanwhile, mix together flour, sugar and salt in saucepan. Slowly stir in milk until combined.

Heat over medium heat until starts to thicken, stirring constantly.

Next stir some of the hot mixture into the eggs, stirring quickly. Then immediately add egg mixture back into hot mixture and stir quickly to combine. Let cook over medium until bubbly and cook an additional minute.

Next stir in chopped chocolate until dissolved and smooth.

Remove from heat and stir in butter and vanilla extract. Cover with film directly on chocolate mixture and let cool at room temp.

Pastry

Place sheet of pastry on backing sheet. Cut into 8 pieces, do not prick with fork. Brush lightly with egg wash and bake at 425 for 15 minutes.

Remove from baking sheet and allow to cool.

Split open and spread chocolate. Enjoy your homemade chocolate pastry!