For the best flavor, use a high-quality vanilla extract. If you don't have time to make homemade pie crust, store-bought crust will work in a pinch. Be careful not to overheat the custard, as it can curdle. If this happens, you can try blending it with an immersion blender until smooth. The frozen cherry pie filling can be a bit hard to break apart. Let it sit at room temperature for a few minutes before breaking it into chunks.