preheat the oven to 180° Celsius

melt the butter in the microwave and cool slightly

sieve the flour, sugar, salt and baking powder into a large bowl

add the mushrooms and the apricots and mix in well

in a small bowl whisk together one of the eggs and the yolk of the second egg, the vanilla extract and the butter

retain the second egg white and whisk slightly to break it up in case you need it to bring the dough together

make a well in the middle of the dry ingredients and pour the egg and butter mix into it

stir until it forms a dough, you might need to add some or all of the left over egg white to achieve this

divide the dough into 2 equal pieces

very lightly dust a work surface with a little flour and shape into 2 logs, each about 20cm long

cover a large baking sheet with non-stick baking paper and place the logs on it leaving plenty of space between them

bake for 40 minutes until golden brown and firm to the touch

remove from the oven and cool for 20 minutes

using a sharp knife slice the biscotti logs on the diagonal into slices and arrange standing up in a single layer on the baking sheet

return to the oven for 20 minutes to allow them to crisp up