Preheat oven to 325°F. Line a baking sheet with parchment or a silicone baking mat. Place 6 tart rings (3 1/2 inch by 3/4 inch) on the mat.

Divide pastry dough into 6 pieces. One by one, place between two pieces of parchment and roll out large enough to fill tart ring. Press in and trim away excess dough.

Pierce the bottom of each tartlet several times with a fork. Freeze for 20 minutes.

Place nuts on a baking sheet and bake until golden and toasted, 8 to 12 minutes. Set aside to cool completely.

Remove tartlets from freezer and bake until golden brown, about 35 minutes. Let cool completely, then remove rings.

Place corn syrup in a large heavy-bottomed saucepan over high heat. Bring to a boil. Add sugar in thirds, stirring enough to incorporate. Cook about 3 minutes until sugar is dissolved and temperature is 350°F.

Reduce heat to medium and quickly stir in butter. Gradually stir in the first portion of cream. Continue to cook, stirring, until temperature is 248°F.

Remove from heat and stir in remaining cream.

Fill each tartlet crust with nuts. They'll be quite full. Pour hot caramel sauce over the nuts, trying to coat completely.

Let each tartlet cool to room temperature, about an hour, before serving.