- Preheat oven to 400°F (200°C). 
- In a saucepan, combine butter, water, and salt. Bring to a boil. 
- Remove from heat, add flour, and stir until a dough forms. 
- Add eggs one at a time, mixing well after each addition. 
- Transfer dough to a piping bag and pipe onto a baking sheet. 
- Bake for 20-25 minutes or until golden brown. 
- For the filling, whip the heavy cream, sugar, and vanilla extract until stiff peaks form. 
- For the topping, heat the chocolate chips and heavy cream until smooth. 
- Once the pastries are cool, fill with cream and top with chocolate.