Preheat the oven to 180 ° C (convection 160 ° C). Grease a springform pan.
For the base, mix the flour, nuts, sugar, vanilla sugar, baking powder and salt together. Whisk the egg.
Add egg and butter to the flour mix while kneading. Knead everything. The dough then becomes like streusel, i.e. a ball. Put half of the crumble in the refrigerator. Spread the other half in the baking pan and press on. Pre-bake the base on the middle rack for 12-15 minutes, then allow to cool.
Wash off the lemon. Rub the peel finely. Squeeze the fruit. Mix together eggs, sour cream, sugar, vanilla pudding powder, lemon juice and zest. Peel and core the pears and cut into wedges
Spread the cream on the floor. Spread the pears on top. Sprinkle with the remaining sprinkles. Bake for about 45 minutes. Let cool and dust with powdered sugar.