In a mixing bowl, combine the softened butter with the sugar, add the eggs, then pour in the ground hazelnuts. Stir until you have a smooth batter. Then pour the mixture over the pastry.
Peel the pears, remove the core, then cut the fruit in half or into thin slices. Arrange the pears on top of the hazelnut cream. Sprinkle with a few crushed hazelnuts (optional).
Bake for 30 to 35 minutes and monitor the cooking until the pie is golden brown.
