Preheat oven to 180°C
Arrange Biscoff bikkies face down in a single layer on a lined baking tray
In a pot, melt butter and brown sugar together, stirring until it bubbles
Continue to stir and cook for three minutes after bubbling
Pour the butter and sugar mixture over the biscuits and spread evenly
Bake for five minutes
Remove from oven and immediately sprinkle white chocolate chips on top
Let the chocolate melt slightly and spread out until smooth, or pop back in oven for one minute if needed
Swirl melted Biscoff spread on top
Sprinkle crushed Biscoff bikkies over the top
Finish with a grind or two of salt
Refrigerate until firmly set
Break into pieces and serve
