Pre-heat oven: 180°C / 160°C (fan) / Gas 4 / 350°F

In a heatproof bowl, melt the butter and white chocolate either in the microwave (20secs at a time) or over a double boiler, stirring until smooth.

In a separate mixing bowl, beat the eggs and sugar using an electric mixer. This should whip up thick and creamy like a milkshake and can take roughly 5mins.

Pour the cooled white chocolate mixture over the eggy mousse, add in the vanilla extract and salt, then gently fold together.

In a separate bowl, sieve the plain flour and matcha powder, whisking together until combined.

Add the wet ingredients into the dry mixture, slowly folding in until almost combined, before stirring in the white chocolate chips.

Pour the mixture into a greased and lined 8-inch square baking pan and bake for 20-25mins, until papery and cracked on top, but with a slight wobble in the middle.

Allow the brownie to cool in the tin before removing and cut into squares.