- Preheat the oven to 190°C/fan 170°C/gas 5.
- Grease a 23cm square tin with a little butter.
- Cut a piece of greaseproof paper so that it covers the bottom of the tin and overlaps on two sides – this will help you get the cooked brownie out.
- Place the chocolate and butter in a large bowl, set over a pan of simmering water and heat gently.
- Don’t let the water boil rapidly and touch the bottom of the bowl. Stir until the chocolate and butter are melted.
- Remove from the heat and add the sugar. Stir until well combined.
- Leave to cool for 5 minutes.
- Add the eggs and egg yolk one by one, beating well after each egg. You should have a dark glossy mixture.
- Add the ground almonds, salt, flour and baking powder.
- Using a metal tablespoon, gently fold in the dry ingredients using a figure of eight movement. Don’t over-mix.
- Pour the mix into the tin, smooth off the surface with a flat knife and bake for 20-25 minutes.
- It should be set but with a little gooeyness in the middle.
- A good way to test if it's done is to push a skewer into the middle. When you take it out it should be fairly clean, but with a few moist crumbs sticking to it.
- Whilst the brownie is baking, roll out the chocolate fondant icing and using a bat-shaped cookie cutter, cut out bat shapes from the fondant.