Preheat oven to 350°. Line a baking sheet with parchment paper or a silpat.
Crush peppercorns and fennel using mortar and pestle or place them in a ziplock bag and lightly smash with a rolling pin or meat mallet. Don’t completely pulverize the spices, the little bursts of pepper and fennel are nice as you eat the biscotti.
In a medium bowl, whisk together flour, cornmeal, baking powder, salt, rosemary, crushed peppercorns, and fennel.
In the bowl of an electric mixer, beat together eggs and sugar until well combined, about 1 minute on high speed. Lower the speed and add the dry ingredients. Mix until just combined. Stir in almonds and raisins.
Divide the dough in half. Form each half into an 8 inch log and place on the prepared baking sheet. The dough will be a little on the sticky side, wetting your fingertips will make this task more manageable. Bake until the logs are lightly golden, about 30 minutes. Cool for an hour (or more) before proceeding.
Cut the logs in ¼ inch increments. I find a sharp chef’s knife makes a cleaner cut than a serrated bread knife (which would be my first thought). Place the biscotti back on the lined baking sheet and return to a 350° oven for 18-20 minutes, until crisp and golden. Cool and serve with cheese or snack on them plain. Biscotti will last a week or so in an airtight container at room temperature.