Butter Tart Squares

Two nights ago I hepled a friend make butter tart squares for a brunch the next day. I've make them before successfully and we had decided to use an easy recipe from Clueless Baker. There is no corn syrup in this recipe but do turn out nicely. Anyways, I made the shortbread crust and she prepared the filling including walnuts and chocolate chips. Separately, both parts were good, but when we baked them, the filling bubbled up a lot around the edges. I thought that was strange since they usually don't and the top is a thinly set crust with the gooey centre underneath. No matter, I thought, it was 12:30am and I was tired. They next day I cut them into squares and cut off the edges where the filling had gotten hard. They cut great but the crust tasted like crunchy sugar, not shortbread. So when you took a bite, it was overwhelmingly sweet and granular - not pleasant. I think some squares turned out fine but mine was not good at all. My husband thought he bit into a chunk of brown sugar (which I told him was impossible). I'm just too picky...everyone else who tried one liked them. (I think) Of course, the store bought marble coffee cake was popular (yuck) and the baklava from Paramount was fantastic.