Good old Betty Crocker-she sure knew what she was doing! She was so good that her ideas have been around since 1921 and selling main stream products all the time.
As promised, I have included my experience in making these sauces that topped my lemon bars from a few days ago. The key is absolutely whole and fresh ingredients! The other key, following Ms. Crocker's recipe without many changes since she knew what she was doing.
The lemon sauce needed about one lemon to produce the needed juice and zest. However, I had some help with the zest from the lemons needed to make the bars-so to be safe you might want more than one lemon. Don't forget to roll it like I shared before for easier juicing!
The raspberry sauce called for frozen raspberries in sauce (or juice), but I just purchased a 6 oz. package of fresh and that seemed to work just fine. The most important aspect of this sauce was using the strainer to pour the cooked sauce through to take out all the seeds. I had NO idea one container or fresh berries would have that much sauce. It will make a much cleaner looking sauce in the end for not much more effort involved. One variation I think would be good is adding fresh mint leaves to the sauce while it is still in the saucepan but strain them out for the final product. Mint and raspberry go well together, so I can see a little flavor from the fresh leaves giving it a nice touch!