Preheat oven to 350 degrees. Line a flat baking sheet with parchment paper or a silicon baking mat.
Break the almond paste up into the bowl of a food processor and pulse several times until it is finely crumbled. Add the eggs, oil, vanilla and almond extracts, almond flour, baking powder, and salt. Process until the mixture forms into a dough. Scrap down the mixture; add the sliced almonds and pulse briefly several times just to combine the almonds.
Divide the dough in half and form into two logs about 9 inches long, 3 inches wide and 1 inch high on the prepared baking sheet. Bake for 25 – 30 minutes or until it starts to brown around the edges. Leave the oven on. Let cool on the pan for 10 minutes. Remove the logs to a cutting board and slice on the diagonal into ½ inch pieces using a serrated knife (important or the biscotti may crumble.) Remove the parchment or silicon baking mat from the baking sheet and place the biscotti on the pan lying on their sides. Bake for 10 minutes, turn the biscotti over and bake for another 10 minutes or until golden brown. Let cool for 30 minutes on the pan.
Note: If you do not have a food processor you can still make these biscotti. Simple grate the almond paste into a mixing bowl with a box grater, add the eggs, oil, and extracts and beat with a hand mixer for 2 minutes. Combine the almond flour, baking soda and salt in another mixing bowl and whisk to combine. Add the flour mixture to the wet ingredients and beat. Stir in the sliced almonds and proceed from there with the recipe.