Rinse raisins, drain and mix with 75 ml rum in a bowl, leave to stand for at least 3 hours. Mix the speculoos and 50 g walnuts finely in a universal chopper. Melt 100 g butter in a saucepan.
Mix the cookie and walnut crumbs with the butter. Spread the bottom of a springform pan (26 cm Ø) with oil. Add the breadcrumb mixture and press it down to a smooth base, chill for about 30 minutes.
Mix cream cheese, eggs, 75 g sugar and starch with a whisk until smooth. Season to taste with cinnamon, cloves and nutmeg. Carefully fold in 100 g rum raisins. Smooth the cheese mixture on the crumb base and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see
manufacturer) bake for about 35 minutes. Let the cake cool down in the switched off oven with the door slightly open.
Caramelise 75 g sugar in a pot, add 75 g butter, cream and 4 tbsp rum and bring to the boil. Let it simmer at low heat for about 15 minutes until slightly thick. Chop 50 g walnuts and stir into the sauce together with the remaining rum raisins, let cool down.
Cut cake into pieces, arrange on a plate and serve with sauce.