Cultured Butter Rusk Crusts

One thing that sets Japanese panko apart from its Western counterparts is the fact that the crusts of the bread are removed to make pure white breadcrumbs from the fluffiest parts of the bread. This is one of the reasons panko creates such an ethereally crisp crust. The problem, of course, is that you're left with the crusts to contend with. I hate wasting food, so I've found a few ways to use them up. Croutons and bread pudding are a few tasty uses, but my favorite method of using crusts is to make rusk. 

Rusk is one of those obscure European foods that the Japanese have picked up and turned into an entire genre of confections. I imagine it started here as a way to reduce food waste, but today some bakeries are better known for their rusk than they are for their bread. 

The concept is simple, take almost any cake, pastry, or bread. Saturate it with butter, and then apply a liberal dusting of sugar before baking it until the bread is crisp and the sugar juuuust starts to caramelize. 

My trick for next-level Japanese rusk is to use cultured butter. Cultured in this context just means the cream has been fermented before being churned. The result is a butter with a high concentration of diacetyl, the compound responsible for giving butter and cheese its distinctive taste. Put another way; this makes my rusk taste like a decadent cheesecake with a crisp texture that melts away in your mouth.