Chestnut puree is sweetish, but a lot of what is sold in cans is sweetened so do check labels and recipes.
This is a German recipe, but it is from the French/German border. It uses grated chestnut, and makes a fairly dense cake. Also a rather big one...
1kg unpeeled chestnuts, or 800g peeled chestnuts, plus milk for cooking.
125g ground almonds
100g white bread (such as day old crusty rolls)- soaked in milk with the excess well squeezed out.
Vanilla to taste
750ml whipping cream
A little sugar
Peel off the outer coat of chestnuts, then blanch. Peel off brown “skin” from chestnuts. Cook in milk and water until soft, then grate and leave to cool.
Separate the eggs. Cream the butter, then slowly add the sugar, egg yolks, and soaked bread. Mix well, then mix in the ground almonds, cooled chestnuts and vanilla.
Whisk egg whites until very stiff, the fold into mixture.
Pour into greased bottom lined 9” tin and bake in medium oven until cooked (recipe does not specify cooking time)
When cooled, split the cake and sandwich together with whipped sweetened cream, then spread cream over the top and sides. Sprinkle the top with a little grated chestnut