Bake Puff Pastry (6) according to package instructions.
Meanwhile, reduce Heavy Cream (1 cup) until thickened.
Add Sauce Veloute (1/3 cup).
Cut the Boneless, Skinless Chicken Breast (2) into cubes.
Add the chicken to the sauce mixture and heat through.
Melt Butter (1/2 stick).
In a mixing bowl, whisk the Egg (1), Water (1 tablespoon), Lemon Juice (1 teaspoon), Sriracha (to taste), and Kosher Salt (to taste) in a water bath until the egg mixture becomes creamy.
Add the warm butter in tiny increments. If the sauce becomes too thick, add more water; if the sauce is too thin, add more butter.
Remove the top of the pastry shells and fill the cavities with the chicken salpicon.