Peel and quarter the pears and remove the core. Cut quarters into cubes. Cream fat, sugar, salt and vanilla sugar with the whisk of the hand mixer. Stir in eggs one after the other.
Mix flour and baking powder and stir in alternately with 275 ml egg liqueur.
Pour 1/3 of the dough into a greased, flour-dusted ring cake mould (26 cm Ø; 3.5 litres capacity). Spread half of the pears on top. Add another 1/3 of the dough, spread the remaining pears on top and smooth the remaining dough over it.
Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 1 1/4 hours. Remove and let cool on a cake rack.
Roughly chop the chocolate and melt over a warm water bath. Carefully turn the cake out of the mould. Use a brush to spread chocolate on the cake. Place the cake on a plate and chill for about 15 minutes.
Pour 50 ml advocaat over the cake.