Preheat the oven to 350°F (180°C). Line a baking sheet with parchment paper.
Mix the dry ingredients: In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.
Beat the wet ingredients: In a large bowl, beat the eggs, sugar, vanilla, and almond extract until thickened and slightly pale—about 2 minutes.
Combine: Add the dry ingredients to the egg mixture and mix until a thick, sticky dough forms.
Add the mix-ins: Fold in the toasted chopped almonds and chocolate chips until evenly distributed.
To shape the logs, spray your hands lightly with oil (or rub a bit of oil on them) or lightly flour your hands, and then transfer the dough to the prepared baking sheet.
For standard biscotti, form into two logs about 12 inches long and 3 inches wide.
For larger, café-style biscotti (the ones shown here), form into two logs about 10 inches long and 4–5 inches wide.
Pat the tops smooth and even. The dough will spread slightly as it bakes, so leave several inches between logs if making two.
First bake: Bake for 25–30 minutes, or until the logs look puffed through the center, which is normal and a good sign the interior has baked properly. The surface should feel a bit firm to the touch, with cracks beginning to form or that have formed.
Cool slightly: Let the logs cool on the pan for 10–15 minutes before slicing. Reduce oven temperature to 325°F if desired for the second bake.
Slice: Using a serrated knife, gently saw back and forth to cut the logs diagonally into ½-inch slices.
Second bake (to toast): Arrange the slices cut side down on the baking sheet. For classic crisp biscotti, bake 10 minutes per side at 350°F. For lighter, crisper cookies, bake a few minutes longer at 325°F. For a slightly chewy center, bake 7–8 minutes per side instead.
Cool completely on a wire rack—biscotti will continue to firm as they cool.
Let biscotti cool completely, then store them in an airtight container at room temperature—no moisture. Avoid plastic bags or humid areas. For long-term storage, freeze in airtight containers, then re-crisp in a low oven (300°F for 5–10 minutes) before serving. You can also leave them uncovered for a day or two at room temperature provided that the kitchen isn't humid.