Grease 2 muffin tins. Preheat oven to 375º.
In medium bowl, beat butter and sugar with an electric mixer until light and fluff. Add egg yolk, beat well. Gradually sir in flour until mixture is just blended and crumbly. Divide dough into 12 equal balls. Press one into each cup of the 2 muffin pans. Pressing evenly on bottom and up sides. Bake in oven for 12 minutes or until golden brown. Cool on wire racks.
Spread nuts on a baking sheet, in a single layer. Bake for 5 min in oven. Sprinkle evenly into the 12 tart shells.
In a saucepan, stir sugar with butter, corn syrup and 2 tbl of heavy cream. Stirring constantly bring to boil over medium heat, boil for 1 min. Pour over walnuts.
Bake in oven for 10 min or until mixture is bubbly. Place on wire rack to cool.
In a medium bowl, beat remaining heavy cream just until stiff. Refrigerate until ready to serve.
With a sharp knife, loosen edge of pastry from each muffin cup. Lift out gently to a serving plate and serve with chilled whipped cream.
This may also be made into a tart by using a 9” fluted tart pan with removable bottom