Preheat the oven to 180c/350f and line a deep 20cmx30cm baking tin with baking parchment. Leave a little of the parchment overhanging the tray to make it easier to get the brownie out later.
Melt the chocolate and butter together in the microwave in 30 second bursts, giving it a stir each 30 seconds (or you can melt in a bowl over a pan of simmering water - make sure the bowl isn't touching the water though). Stir and leave to cool slightly.
Whisk the eggs and sugar in a large bowl using an electric whisk until thick and creamy. Stir in the orange extract and vanilla extract.
Slowly whisk again, and pour the melted chocolate and butter in. Pour it at the side of the bowl in a thin stream, whisking all the time, so that the eggs don't scramble with the warm chocolate.
When the chocolate is thoroughly mixed in, sieve the flour, cocoa powder and baking powder over the mixture, and then add the ground almonds. Fold into the mix gently, in a figure of eight. This will help to keep the air in.
Pour the mixture into your baking tray, and use a palette knife to ensure it goes all the way to the edges.
Arrange the rolos on top of the brownie mix evenly - in 4 rows of 8. Push the Rolos into the mixture slightly and place the tray in the oven.
Cook for 25 minutes.
Take out of the oven and leave to cool in the tray. Lift the brownie out of the tray using the baking parchment and place on a chopping board. Use a sharp knife to slice the brownie into portions (I cut it into 20-24 pieces). It will crumble slightly when you cut it, but it crumbles less, the longer you leave it to cool.
Decorate with orange zest if you prefer, then serve!