Line a 20 cm/8 inch square cake pan with baking parchment, making sure that it overhangs either side so that it is easy to lift the baked brownies out of the pan. Preheat the oven to 180°C/160℃ fan/350°F/gas mark 4.
Place the sugar, non-dairy yogurt and milk in a pan over a low heat and stir regularly until the sugar has dissolved and the mixture is hot and glossy looking but not quite at boiling point.
250 g (1 ¼ cups) caster or granulated sugar, 80 g (⅓ cup) plain non-dairy yogurt (I use Greek style soy), 100 g (⅓ cup + 4 teaspoons) unsweetened non-dairy milk (I use soy)
Remove from the heat and add the chopped chocolate and butter. Stir until everything is completely melted and the mixture is smooth.
150 g dark chocolate, 75 g (⅓ cup) vegan block butter
Whisk in the orange zest and extract and the vanilla extract followed by the cocoa powder, baking powder, salt and plain flour.
finely grated zest of 2 large oranges, 1 teaspoon orange extract, 1 teaspoon vanilla extract, 60 g (½ cup) cocoa powder, ¼ teaspoon baking powder, ½ teaspoon salt, 160 g (1 ⅓ cups) plain (all-purpose) flour
Gently fold in most of the orange chocolate, reserving some to scatter over the top. Scrape the batter into the prepared tin, spread it level and scatter over the reserved chocolate.
100 g orange flavoured chocolate
Bake for 20-25 minutes until a skewer inserted into the centre comes out gunky with moist crumbs but no wet batter. If it comes out clean the brownies are overbaked so keep an eye on them.
Leave the brownie slab to cool completely in the pan (I like to put it in the fridge overnight once it has cooled so that the brownies are easy to slice neatly), then carefully lift it out using the overhanging parchment and use a sharp knife to cut it into squares.