EnlargeCredit: Artichokes and Garlic
I did a little digging to find out what exactly is a buckle, and this is what I came up with: During
the baking process, the cake batter rises up around the fruit, encasing
the fruit in batter and causing the streusel to buckle, creating a
distinctive crinkly appearance. Well, mine didn't seem to have a distinctive, crinkle appearance, but it was pretty darn good.