Preheat oven to 350°F (175°C). Line a large baking sheet with parchment paper.

Spread whole almonds on another tray and toast in the oven for 5-7 minutes. Let cool.

In a medium bowl, whisk together the all-purpose flour, baking powder, and salt.

In another bowl, cream melted and cooled butter and granulated sugar until well combined. Add eggs, egg yolk, vanilla extract, and almond extract, mixing well until smooth.

Gradually incorporate the dry ingredients into the wet ingredients, mixing until a soft dough forms.

Gently fold the toasted almonds and optional orange zest into the dough.

Turn the dough out onto a lightly floured surface and divide it in half. Form each portion into a log about 12 inches long and 2-3 inches wide. Place the logs on the prepared baking sheet, spacing them at least 3 inches apart.

Bake for 25-30 minutes, or until the logs are firm and lightly golden. Remove from the oven and let cool for 15-20 minutes.

Using a sharp bread knife, slice the logs diagonally into 3/4-inch thick biscotti.

Arrange the biscotti cut-side up on the baking sheet. Return to the oven and bake for an additional 12-15 minutes, until crisp and golden.

Remove the cantucci from the oven and cool completely on a wire rack before serving or dipping.