Caramelize the sugar with the butter. Pour it into a cake form and arrange pieces of peaches on top. Leave it to harden. Beat the eggs with the sugar.
Add the milk, oil and flour with baking powder. Divide the mixture into 2 parts.
To 1, add the coffee dissolved in a little water. Pour the white part over the peaches. Arrange the biscotti on top and pour on the coffee mixture.
Bake at 356°F (180 °C) for 40 min. Take it out and leave to cool. Carefully invert into a suitable plate.