Peel and halve the pears and cut out the core. Cut the pears in a fan shape. Caramelise 100 g sugar in a pot. Add lemon juice and about 2 litres of water and bring to the boil while stirring. Let the pear halves steep in it for about 20 minutes, take them out.
In the meantime, knead butter in pieces, 65 g sugar, flour, 1 egg and ground almonds with the dough hooks of the hand mixer to a smooth dough. Roll out the dough between 2 layers of foil and place it in a greased and lightly floured fat pan (approx. 19 x 34 cm), cut off any protruding dough edges. Put the dough in the tin in a cool place for about 1 hour.
Prick the bottom several times with a fork. Cover the dough with baking paper, add peas. Bake in the preheated oven on the lower shelf (electric oven: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 20 minutes.
In the meantime, stir the sour cream, 3 eggs, 150 g sugar and vanillin sugar with the whisks of the hand mixer until smooth. Stir in sauce powder. Take the baking tray out of the oven, remove baking paper and peas.
Cover the dough with pears and pour over the top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 30 minutes. In the meantime, roast the flaked almonds in a pan without fat until golden brown, remove. Take the cake out of the oven. Heat up jam and 2 tbsp. water. Spread pears with the jam. Sprinkle with flaked almonds.