Preheat the oven to 350°F. Grease two baking sheets with a small amount of olive oil or butter.
In a medium bowl, whisk the flour, dried nut or seed pulp, sugar, baking powder and salt to combine. Stir in the chopped, toasted nuts.
In a small bowl, whisk together the zest, eggs, olive oil and limoncello. Add to the dry ingredients and stir until the dough is well combined. It will be very sticky.
Turn the dough out of the bowl onto a generously floured work surface. Sprinkle a bit of flour on top of the dough. With your hands, press and shape the dough into a rectangle. Add more flour as you work as needed. Cut the rectangle into three pieces with a bench scraper. Shape each piece into slabs, approximately 12 inches long, 3 inches wide and ½ inch high. Using the bench scraper to help you move the slabs of dough, place two slabs on one prepared baking sheet, and one slab on the other.
Bake for 25 minutes. The slabs will be brown around the edges and will spring back and not remain indented when you touch them lightly with a finger. Remove from the oven and place the baking trays on a cooling rack. Let them cool until you can handle them, about 20 minutes.
One by one, place each biscotti slab onto a clean cutting board and cut diagonally with a serrated knife into ¾-inch thick pieces. Arrange the cut pieces evenly on the two cookie sheets, cut sides down.
Bake for 10 minutes. The biscotti will brown more and the centers will be firmer and drier. Flip and bake for 10 more minutes. They are finished when firm and golden. If they are still spongy when you press them, bake them 2 minutes longer. Cool on racks and store in glass jars for up to 2 weeks. These also freeze very well and will keep for up to 3 months.