These sweet potato fudge brownies are so decadent as it is, there is no need for a frosting. When pureed and added to a brownie batter, sweet potato holds moisture and is a plant-based hack to fudgy, dense, rich brownies.
Preheat the oven 175°C (350°F)
First prepare the flax egg. In a bowl, mix the flaxseed powder with water and set aside for 10 minutes to gel.
In a bowl, mix the flax egg with the remaining wet ingredients.
In a separate bowl, combine the dry ingredients. Gently fold the wet ingredients into the dry mix. Stir until just combined. If you prefer some texture to your brownies, fold in the chopped dark chocolate or nuts.
Transfer the batter into a greased brownie pan (9-inch) and spread it out evenly with a spatula. Place the pan in the oven and bake for 30-35 minutes. You can also bake in individual muffin molds for 15 minutes. Test for doneness by inserting a toothpick into the brownies; it should come out clean.
Remove pan from oven and allow to cool to room temperature, then place in the refrigerator for a few hours or in the freezer for 1 hour before slicing. This helps to get nice clean edges. Best served warm with a scoop of your favourite ice cream.
Store brownies in an airtight container in the refrigerator for up to 7 days.
Paleo / Grain-free option: replace oat flour with 15 g (2 tbsp) coconut flour, or use 70 g Bob's Red Mill Paleo Baking Flour (a mix of almond, arrowroot, coconut and tapioca flours) in place of all the flours.
Different root vegetables: I have made this with beetroot and pumpkin puree instead of sweet potato (equal weight) and it came out actually better, more bounce and less like a slab of chocolate.
Lighter cake brownies: omit dark chocolate, increase maple syrup to 48 g (3 tbsp) and coconut oil to 20 g (2 tbsp).