Preheat oven to 160 degrees for a fan forced oven.
Melt butter and mix in with brown sugar and combine well.
Mix in the pretzels
Press into a lined sliced tin.
Bake in oven till golden brown approx 10-12 minutes. This will be bubbly and quite soft, don't panic. Just let it cool down before you place the caramel mixture on it.
Over a low heat combine the ingredients until the mixture is smooth.
Allow to cool before pouring over the pretzel base.
Bake in oven for about 15-20minutes or until golden.
Allow to cool before decorating with chocolate layer.
Melt the chocolate and oil in a heatproof bowl over a saucepan of simmering water; stir until combined and smooth. (You can also melt this in the microwave as you would normally do.) Pour over the caramel mixture and spread evenly.
Allow to set in the fridge for at least 30 minutes before cutting up and serving.