After getting your hands dirty rubbing the butter, flour and icing sugar together to form a dough, the base bakes for around 20 minutes. Just enough time to learn what on earth 'soft ball stage' is. I was going to write about it, but it turns out that this website does it so well, I couldn't even add anything if I wanted to (apart from BE PATIENT).
After you've made the base you scatter the marshmallows on top. I decided to go one up on Hummingbird and use tri-coloured marshmallows which I love (they're from Lidl incase you wondered) even though they aren't mini. I just scattered icing sugar over a knife and chopped them up a bit smaller. Sprinkling the knife with icing sugar stops the marshmallows from sticking to the knife, although you can also dunk your knife in boiling water and this will have a similar effect.
This is where the beauty really begins. Adding the sugars and syrups and boiling it all up is live art, honestly it is (see the vine below for a snippet). The only thing I can say is allow yourself time and be calm as this doesn't just happen - this is not the bish bash bosh job that I normally serve up to you. It's where baking crosses in to science. Fear not you don't need a science degree to master sugar syrup, just keep an eye on it and test it often. Read the article here and you'll get a good feel for where you are on the scale as you go along.
At first it will appear very fluid, but as it boils it will thicken.
This photo below is what I decided was soft ball stage. Not entirely sure if this is what 'soft ball' is but it worked a treat. The syrup held together in the cold water, but I could squidge it between by fingers when I took it out. It was very fun actually.
After you have made your butterscotch you can mix in the butter, vanilla, peanut butter and cream and bring to the boil again.
A little flourish of chopped nuts and you have one very pretty block of Butterscotch and Marshmallow Bar. It's amazing. It reminds me of Pollock. All layers of colours and textures and mess.
Finally you can pour over your base and marshmallows.
BIG BIG FAN.
To chop it up get a mug of boiling hot water and dip a sharp knife in the water before cutting. This means the marshmallow won't stick and pull away from the base. I would advise cutting the squares quite small, as the butterscotch is sickly sweet.