In a microwave, melt the Biscoff spread for the bars for 15 seconds
Place butter in a large saucepan and melt. Allow the butter to begin to brown, with small brown flakes at the bottom. Add the marshmallows, vanilla and salt and stir until melted, about 3 minutes.
Pour the butter marshmallow mixture over the cereal, and then add melted Biscoff spread. Fold, but you don’t want to over mix as we still want thick swirls of cookie butter in the mix
Pour into the prepared pan. Using a spatula, gently press down. Don’t press down too hard or they’ll be too compact
Melt the white chocolate in a microwave. Microwave in short bursts, stirring every 15 seconds, until smooth. Pour over the rice krispie treats and use an offset spatula to cover the cereal evenly.
Melt the biscoff spread in the microwave. Microwave for 15 seconds. Spoon dollops of the melted biscoff on top of the chocolate. Use a wooden skewer or butter knife to swirl together. Gently press cookies on top.
Let it chill in the fridge for at least two hours then slice.
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. I have provided a conversion to US cups but please note that I haven’t tested the recipe with this method. Just click on 'US CUSTOMARY' above ingredients.Biscoff Spread: you can also use Cookie Butter from Trader Joes if you don't have Biscoff. Butter: I use European style butter, like Kerry Gold, in my recipes. This will make your finished bake much creamier and richer.Salt: If you don't have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt.Storage: slice the treats into 16 bars and keep in an air tight container for up to 5 days. I do not recommend freezing these as it will alter the texture.