Mrrzy, this is my favourite flourless cake recipe. It's not chocolate, but I've used similar ingredients but less eggs and added melted chocolate to make chocolate brownies. I have used the processed almonds & eggs idea for a few different experiments including a crumb base for a chocolate ganache tart and I've liked the results of everything I've tried so far.

The main idea is to use processed almonds or almond meal instead of flour and lots of eggs to bind it together and slow cook it in the oven to allow the eggs to do their thing. Variations on flavour can be made by using a different fruit, e.g. stewed apples, peaches or apricots, etc.

Orange & almond cake

Note: I also make the orange syrup from a slightly different cake recipe to pour over the cake. See below.

Makes 1 cake
Ingredients
•        2 large navel oranges, (choose oranges with unblemished skins as the whole fruit is used in this recipe)
•        5 eggs
•        1 1/4 cups (250g) caster sugar
•        2 1/2 cups (250g) ground almonds OR whole almonds processed in a food processor to the desired crumb size
•        1 tsp gluten-free baking powder*
•        Pure icing sugar to serve
Method
1.        Preheat oven to 170°C. Grease and line the base of a large cake pan.
2.        Place the two whole oranges in a large microwave safe bowl, cover with water and put a plate on top to keep the oranges under water. Bring to the boil and simmer, covered, for 20 minutes ensuring that the oranges remain covered with water. Drain and cool. Chop the oranges into quarters, discard any seeds, then place the chunks including the rind into a blender and puree until smooth.
3.        Beat the eggs with the sugar until thick, then add the orange puree, ground or processed almonds and GF baking powder and mix well.
4.        Pour into prepared pan and bake for 1 hour. Leave the cake to firm up in the pan for 20 minutes then turn out, remove the baking paper and turn over to finish cooling right way up. This cake definitely mellows with a little time and can be prepared up to 48 hours in advance.
5.        To serve, sift icing sugar on top and decorate with orange zest and almonds. OR poke a some holes in the cake pour orange syrup over the top. See recipe below for orange syrup.
Source

Orange & almond cake

Orange Syrup
•        1 orange
•        155g (3/4 cup) caster sugar
To make the orange syrup, use a zester to remove the rind from the orange. (Alternatively, use a vegetable peeler to peel the rind from orange. Use a small sharp knife to remove white pith. Cut rind into thin strips.) Juice orange.
7.        Step 7
Place rind in a saucepan of boiling water and cook for 5 minutes or until soft. Drain. Return to pan with orange juice and sugar. Place over low heat and cook, stirring, for 2-3 minutes or until the sugar dissolves and the syrup thickens.
8.        Step 8
Turn cake onto a serving plate. Use a skewer to gently prick the top. Spoon over syrup. Cut into wedges to serve.