Preheat the oven to 180°C/Fan 160°C/gas 4. Cut a rectangle of non-stick baking parchment to fit the base and sides of the tin. Grease the tin and then line it with the paper, pushing it neatly into the corners

Measure all the ingredients into a large bowl and mix with a hand-held electric mixer until evenly blended

Spoon the mixture into the prepared tin, scraping the sides of the bowl with a plastic spatula to remove all of it. Spread the mixture gently to the corners of the tin and level the surface with the back of the spatula

Bake for 40–45 minutes, until the brownies have a crusty top and a skewer inserted into the centre comes out clean.Cover loosely with foil for the last 10 minutes if the mixture is browning too much. Allow the brownies to cool in the tin and then cut into 16 pieces. Store in an airtight tin