Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, whisk together the flour, baking powder, ground cinnamon, and salt. Set aside.
In another bowl, cream together the softened butter and granulated sugar until light and fluffy (about 3-4 minutes).
Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract.
Gradually incorporate the dry ingredients into the wet mixture, mixing until just combined. If using, fold in the sliced almonds and chocolate chips.
Divide the dough in half and shape each half into a log about 12 inches long on the prepared baking sheet, flattening them slightly for even baking.
Bake for 25-30 minutes, or until golden and firm to the touch.
Remove from the oven and let the logs cool for about 10 minutes.
Using a sharp knife, slice each log diagonally into 1/2-inch thick slices.
Place the slices cut side down back on the baking sheet and bake for an additional 10-15 minutes, turning them halfway through, until they are crisp and lightly browned.
Remove from the oven and allow the biscotti to cool completely on a wire rack.
Notes
Serve the biscotti in a clear glass jar or on a decorative plate. Pair with a side of espresso or tea for a delightful treat!