Preheat the Oven: Start by preheating your oven to 350°F (175°C). Line a baking sheet with parchment paper for easy cleanup.

Mix the Dry Ingredients: In a mixing bowl, combine the flour, sugar, baking powder, and salt. If you’re using orange zest, add it here as well. Mix well to ensure all the dry ingredients are evenly distributed.

Add the Wet Ingredients: In another bowl, beat the eggs and vanilla extract together. Gradually add this mixture to the dry ingredients, stirring until a dough begins to form.

Incorporate the Nuts: Fold in the whole almonds or hazelnuts. If you prefer a nut-free version, you can substitute the nuts with dried fruits or chocolate chips.

Shape the Dough: Turn the dough out onto a floured surface. Divide it into two equal portions. Shape each portion into a log about 12 inches long and 2 inches wide. Place the logs on the prepared baking sheet, leaving space between them as they will expand during baking.

First Bake: Bake in the preheated oven for about 25-30 minutes, or until the logs are lightly golden.

Cool and Slice: Remove the logs from the oven and let them cool for about 10 minutes. Once they are cool enough to handle, use a serrated knife to slice them diagonally into 1/2-inch thick pieces.

Second Bake: Place the slices back on the baking sheet, cut side down, and return them to the oven. Bake for an additional 10-15 minutes, until they are crisp and golden brown.

Cool Completely: Once baked, remove the biscotti from the oven and let them cool on a wire rack.

Variations and Substitutions

Flavored Biscotti: Add spices like cinnamon or anise to the dough for extra flavor.

Chocolate-Dipped: Dip half of each biscotti in melted dark or white chocolate for a sweet twist.

Nut-Free: Substitute nuts with seeds (like pumpkin or sunflower seeds) or omit them entirely for a nut-free version.

Gluten-Free: Use a gluten-free flour blend in place of all-purpose flour.