Start by making the tart dough. Sieve the flour on the table. Make a well in the flour. Pour the sugar, the butter and the egg into the middle of the well.Knead the dough very well till it’s smooth and elastic. Cover the dough with tin foil. Place it in the fridge for one night. Next morning, make the vanilla cream. Bring the milk and the sugar to the boil. Thicken with the vanilla powder. Heat the oven to 220°C degrees. Grease the mould with butter and flour. Roll out the dough and place in the mould. Pour the cream over the dough.Next, peel and slice the apples. Put the apple slices on the pie. Brush the crust with some egg. Put the pie in the oven at 220°C for 30 to 35 minutes, depending of the power of the oven. Take the pie out of the oven, let it cool down and take it out of the mould. Mix all the ingredients for the coulis. Heat it so it thickens. When it is ready, add the Grand Marnier. Pour it over the pie.
When the sauce has cooled, serve the pie.