No no, it’s not some new urban slang:
Butter Tarts | Baking Bites
A butter tart is a Canadian specialty that, unless you have friends or family living up North, you may never have experienced. I’ve certainly never seen them sold in any bakery around here. The pastries are made with a tart shell that is filled with a mixture of sugar and butter, held together with eggs. Often, the tart filling includes raisins or chopped nuts, but a plain tart is pretty standard - and pretty darn tasty, too.
Those look pretty damn delicious. The description of “like a pecan pie without the pecans” sure sounds right to me.