200 g (7 oz) plain or orange-flavoured dark chocolate, broken into pieces
3 large eggs
seeds from 1 vanilla pod
75 g (3 oz) dark soft brown sugar
100 g (3½ oz) caster sugar
75 g (3 oz) self-raising flour
298 g (10 oz) can mandarin segments in juice, drained
Line a 23 cm (9 inch) square cake tin with baking paper, allowing it to stand a bit above the edges.
Warm the butter and chocolate in a small pan over a low heat, stirring occasionally, until just melted. Set aside.
Meanwhile, put the eggs, vanilla seeds and sugars into a large bowl and beat until thick and pale. Sift in the flour, mix well, then stir in the melted chocolate.
Fill the prepared tin with the brownie mixture and sprinkle the mandarin segments over the top.
Bake in a preheated oven, 190˚C (375˚F), Gas Mark 5, for about 20 minutes, or until just firm to the touch but with a slightly fudgy texture. Cool slightly in the tin, then lift on to a board and cut into squares to serve.