Who’d of think it? Sponge toffee crunched up into a streusel is the crowning glory on this wonderful coffeecake. Ever wonder what you fan do with sponge toffee? It looks so good but eats too sticky! It is, however, perfect for some funky baking. Buttermilk makes a good stand in for sour cream if you’ve a mind to use it. This caves in a bit after baking (because of the cream cheese topping) but is a golden delight.