Preheat the oven to 170°C/150°C Fan. Line two baking sheets with parchment or baking paper. Set aside.
In a large mixing bowl, whisk together the room temperature butter, sugar, salt and vanilla until smooth and creamy. Add in the eggs and whisk until smooth and creamy.
90 grams butter, 2 large eggs, 2 teaspoons vanilla extract, 150 grams caster sugar
Add in the lemon zest, juice of a lemon and vanilla extract, whisk through to combine.
2 tablespoons of fresh lemon juice, zest of 2 lemons
Add in the flour and baking powder, and mix through using a silicon spatula or wooden spoon until you have a smooth dough. Pour in the chopped almonds and mix through.
300 grams plain flour, 2 teaspoons baking powder, 1 cup chopped raw almonds
Divide the dough roughly into two. Take one half and make a rough sausage shape (about 20-25cm long, 3-5cm wide) before placing it on the baking sheet. Once it is on the baking sheet, smooth out the dough and flatten it until about 2cm tall. Repeat with the other half of the dough.
Bake for 30 minutes, the log will be very pale in colour. Remove from the oven and allow to cool for 15 minutes. Using a sharp chef's or Santoku Knife or even a serrated knife, slice the log either straight across or at a slight diagonal, approximately 1.5 to 2.5cm in thickness.
Place the sliced biscotti, bottom side down pack on the baking sheet and return to the oven for an additional 25 to 30 minutes. This will dry out the biscotti and give it a nice golden brown colour. Once baked, allow to cool on a wire cooling rack.
Combine the icing sugar and lemon juice and mix to form a glaze. Drizzle the glaze over the cooled biscuits, and allow the glaze to set before serving.