This recipe is gluten-free, and is usually dairy-free and normal-sugar-free when I make it, because I normally make it in a context where those things are useful.

ingredients
200g butter/dairy-free baking-suitable wossname (usually we use Pure Soya)
300g dark chocolate (70%+)

5 eggs
250ml agave syrup (or 400g sugar)
1 tsp vanilla essence

300g roasted hazelnut meal
1 tsp baking powder

2 handfuls raspberries (frozen or fresh)

method
1. melt chocolate and butter or substitute together (I use a pyrex bowl balanced over a saucepan of simmering water; I gather the microwave works fine too)
2. meanwhile, beat the second group of ingredients together until they're well-mixed [NB if you are feeling REALLY ENTHUSIASTIC you can separate the eggs, and put the whites to one side to beat later]
3. add chocolate mixture to egg mixture, beating well
4. add hazelnut meal and baking powder, mixing until combined [if you are feeling REALLY ENTHUSIASTIC, now is the time to beat the egg whites and fold them gently in]
5. scatter the raspberries over the bottom of the tray you're baking this stuff in; pour the brownie mix over; bake in 180degC oven until no longer ridic wobbly (~30min)

variations
add appropriate booze.
use Maya Gold Green & Black's plus orange booze of some description (possibly with !hazelnuts).
substitute almond meal for hazelnut; place peeled, cored and halved pears in the baking bucket, and add a mixture of nutmeg, cinnamon and allspice to the batter.