Line the springform baking tin with baking paper.
Gently warm the eggs through, add with the sugar and stir until frothy. Sift both flours and carefully fold them into the eggs.
Pour into the cake tin and bake at 200°C for 10 to 15 minutes.
Allow to cool, then remove the sponge from the tin and slice off the top. Return the sponge base to the cake tin and set aside.
Soak the rye bread in the milk and sugar for one to two hours.
Bring the rye bread mixture to the boil, puree with a hand blender and allow to cool to approximately 50°C.
Squeeze out the soaked gelatine and stir it into the in the warm rye paste until completely dissolved.
Quickly beat the mixture, add the whipped cream, spread on and smooth over the sponge base (steps below).
Crumble the leftover piece of sponge, sprinkle over the tiramisu, and chill. Cut it into pieces and serve with a rye crisp.
For the rye crisps, slice the rye bread thinly, brush with butter and dip in the sugar. Then caramelise in a frying pan until golden brown.