To make the orange almond biscotti dough:

1. Finely grate the oranges zest with a box grater or a zester and set the zest aside. Cut one of the oranges in half and squeeze out 1 tbsp of juice. Set the juice aside too.
2. Sift together the flour, baking powder and salt into a bowl.
3. Beat the butter and sugar in a large mixing bowl with a hand mixer at medium speed until light and fluffy, about 2 minutes.
4. Add the eggs, orange zest and juice and beat again for 2 minutes.
5. Add the flour mixture and beat at a lower speed until just incorporated. You might need to scrape down the sides of the bowl with a rubber spatula to blend in everything.
6. Tip the almond meal and the almonds into the bowl and mix them in with a spatula.

To shape the biscotti:

1. Preheat your oven to 175°C (345°F) and line a baking sheet with parchment paper.
2. Scrape the biscotti dough onto the lined baking sheet and shape into a log about 9cm (3 ½ in) wide and 28cm (11 in) long. It might be easier for you to do with slightly damp hands.
3. Bake for 35 min, the log should be pretty golden by then. Take out of the oven and let the log cool down for 30 min.
4. Reduce the oven temperature to 150°C (300°F). Carefully transfer the log to a cutting board and peel off the parchment paper if it’s stuck. Cut the log into 1,5cm (½ in) thick slices in a back and forth motion using a serrated knife. The edges of the longer biscotti slices might crumble up a bit so be delicate.
5. Place the slices on the lined baking sheet flat side down and bake for 15 min. Take the sheet out of the oven and gently turn the biscotti over.
6. Return the sheet to the oven and continue baking for another 15 min, until golden brown.
7. Place the biscotti on a wire rack to cool completely before eating.