If making your own caramel add granulated sweetener into a small pot with about 1/2 tablespoon of water. Let the sugar dissolve in the water, then bring to a boil, lower the heat and let it simmer over medium heat until caramelized. Keep an eye on it so it doesn't burn, but do not stir, otherwise it might crystalize. This takes about 4-5 minutes. Add 1/2 tablespoon of cream, stir together, pour into a small bowl and place in the fridge to harden.
Preheat the oven to 175 degrees Celsius.
Grease two small bowls/tins with cooking spray. Add a little bit of cacao powder and shake it around to coat evenly, ensure both the bottom and sides are well covered and no "empty" patches remain. Ta the excess out. Place on a baking sheet.
Combine cacao powder, rice flour, granulated sweetener and salt in a small bowl.
Add eggs and fiber syrup/agave/honey to another small bowl, whisk to combine.
Add the dry ingredients to the wet, whisk until combined.
Divide half of the batter between the two molds. Remove the caramel from the fridge, divide between the two molds, placing it in the middle of each mold. Top with remaining chocolate batter.
Bake in the middle of the oven for 10-12 minutes. Remove from the oven, let it rest for about 1-2 minutes.
Run a knife around the edges gently to make sure the cake hasn't stuck. Place a small dessert plate over the top of each ramekin and carefully turn it over, inverting the cake onto the plate. Let stand for about 10 seconds, then remove the ramekin to unmold the cakes. Top with more cacao powder (or icing sugar). Serve as is, with ice or whipped cream.