Heat the oven to 180C (160C fan) gas 4. Grease and line a 25 x 18cm tin with a non-stick teflon sheet.
Melt the butter in a saucepan over a low heat.
Add the honey and sugar, stir and bring to the boil.
Simmer for 5 minutes, then remove from the heat.
Stir in the muesli and mix together well.
Press into the prepared tin.
Bake for 25 minutes or until golden.
Cut into bars whilst warm.
Best left until the day after making for maximum enjoyment.