Method

1. Bake tart shells according to package directions.
2. In a small saucepot, heat cream over medium heat just until steaming.
3. In a bowl, whisk egg to blend.
4. Gradually whisk about half of the hot cream into the egg; whisk egg mixture back into pot.
5. Cook over medium heat whisking constantly until slightly thickened and just about to boil, about 2 minutes.
6. Remove from heat; stir in chocolate, hazelnut butter and vanilla extract until smooth.
7. Pour filling into tarts.
8. Garnish with chopped hazelnuts (Can be covered loosely and refrigerated for up to 1 day).
9. Tarts can be served cold or warm. Warm tarts in a 350 degree F (180 degree C) oven for 5 min or until warmed through.