Preheat oven to 350 F. Grease or paper line a standard sized muffin tray.
In blender, place prunes, cocoa powder, and hot coffee and let rest 30 minutes. Then, add egg yolks, oil, and vanilla; blend until smooth.
In large bowl, stir together oat flour, baking powder, cayenne, and salt. Add cocoa mixture to oat-flour mixture and stir gently until combined.
Using electric mixer or hand whisk, whip egg whites until soft peaks form.
Stir about 1/4 of whipped egg whites into oat flour mixture, then gently fold in remaining whipped egg whites.
Divide batter among 10 prepared muffin cups and bake in preheated oven for 18 minutes, or until cakes are set and tops look slightly damp. Let rest for a few minutes before unmoulding.
To make sauce, in blender, combine raspberries, honey, lemon juice, and 2 Tbsp water and purée until smooth. Strain through fine-mesh sieve, pressing with a wooden spoon or spatula to help separate the seeds from the purée.
In small saucepan, heat raspberry sauce until warm to the touch.
To serve, spread some warm raspberry sauce on small plates and top with chocolate cakes. Garnish with shaved chocolate, if desired.