Preheat the oven to 180oC/350oF/Gas
4. Grease a 23cm springform tin. Sift together the flour, baking powder
and salt, and set aside.
In a medium saucepan over a moderate
heat, melt the white chocolate, sugar and butter until smooth, stirring
frequently. Cool slightly, then beat in the eggs and vanilla.
Stir in the chocolate chips. Spread
evenly in the prepared tin, smoothing the top.
Bake for 20-25 minutes until a
toothpick inserted 5cm from the side of the tin comes out clean. Remove
form the oven to a heatproof surface, sprinkle chopped milk chocolate
over the surface (avoid touching the side of tin) and return to oven for
Remove from the oven, and using the
back of a spoon, gently spread out the softened chocolate. Sprinkle with
the macadamia nuts and gently press into the chocolate. Cool on a wire
rack for 30 minutes, chill for 1 hour.
Run a sharp knife around the side of
the tin to loosen, then unclip and remove.