Preheat your oven to 325°F (163°C).
Soften the butter in a microwave-safe bowl for approximately 10 seconds, then transfer it to a large mixing bowl.
Add sugar to the butter and use an electric hand mixer to cream the two ingredients together until the mixture is smooth and well combined.
Gradually whisk in the eggs, followed by the almond and vanilla extracts, blending until all ingredients are fully incorporated and the mixture is homogeneous.
Gradually add in the flour and baking powder, carefully whisking until there are no dry spots in the dough.
Fold in the almond slivers, ensuring they’re evenly distributed throughout the biscotti dough.
Divide the biscotti dough in half. Shape each half into a log, approximately 8 inches long and 4 inches wide, on a baking sheet.
Bake the logs for about 35 minutes. After baking, remove the biscotti logs from the oven and let them cool for 5 minutes.
Once the logs have slightly cooled, use a sharp serrated knife to slice them into the classic biscotti shape. Spread the sliced biscotti over the baking sheet.
Return the biscotti to the oven and bake for an additional 20-25 minutes, flipping the biscotti halfway through to ensure even baking.
Serve the biscotti immediately, or allow them to cool completely before storing. Enjoy with your favorite beverage!