Brown the butter until it smells nutty and delicious.
Add the sugar, condensed milk and golden syrup and cook, stirring, until darkened and thickened.
Stir through salt and vanilla.
Add the mallows and stir till combined over heat.
Add the Krispies and stir thoroughly.
Pour into a lined tin, mine was approx 22cm square, and press gently until it's smooth and fills the tray to the corners.
When cool, cut into bars or squares and if you like drizzle with a little dark or milk chocolate.
