For the crumble, place all ingredients in a food processor and pulse until the crumble comes together. It will look more wet than a typical dry crumble. This will enable you to get larger moist pieces, versus small and dry crumbles.
Preheat oven to 350°F.
Coat a 10-inch springform pan with butter and lightly dust with flour, shaking out any excess.
Place the marzipan, sugar, and butter into the bowl of an electric mixer. Start on low to break up the large chunks of marzipan and gradually work up to a medium-high speed.
Mix for 2-3 minutes until the mixture is smooth and begins to lighten in color. Add the eggs, one at a time, mixing thoroughly after each addition. Turn the mixture up to high and beat until the mixture is light and fluffy, about 2 minutes. Add the dry ingredients and spices and mix on low for 10 seconds.
Remove the bowl from the mixer and using a spatula fold in the remaining dry ingredients. This is so you do not overwork the dough and end up with a tough cake.
Scatter the pears on top of the batter, spreading evenly. Top with crumble, again making sure it is evenly distributed.
Bake for 70-85 minutes. The cake will be golden brown and the edges will have pulled away from the pan. Allow to cool in the pan for 1 hour before unmolding.
Serve with crème fraîche and slip away into bliss.