I’ve been experimenting with variations off my grandmother-in-law’s lemon bar recipe lately. It started relatively innocently! Although I’d never seen her do it, her recipe had an option to replace most of the lemon juice with lime, so I tried it. Meanwhile, in the lemon recipe (since I needed lots of bars to bring to a pot luck) I tripled the juice and then reduced it to the right volume of liquid. These both turned out great, though the crusts were a little bit too crumbly for my taste and I used too much lime zest in the first batch. The second batch of lime got less zest and less juice, so they were weak but okay.

So, this week I decided to experiment with grape bars. I bought some grape juice, and decided to try a peanut-butter cookie crust. I used the Joy of Cooking recipe for classic peanut-butter cookies, and started with 1/2c of grape juice. That wasn’t very grape, so I added more—eventually, 2 cups. (It was too late to reduce it, by this time, so I just hoped it would boil off.) 25 minutes later, I had something that looked a lot like brownies—from the top. It was very dark, so though it was purple it could’ve easily been mistaken for brown. The underlayers, though, are very clearly brown, and full of bubbles like a bread pudding. Here is a UFO-spotting quality picture:

It is, alas, almost entirely peanut-butter flavor. The grape is only detectable if you have a very subtle palate, or if you eat some of the top purple layer alone. Otherwise, it’s mostly peanut-butter. Where did I go wrong? My guesses:

• I didn’t bake the crust enough: If the peanut butter cookie was still quite soft, the liquid would have soaked in rather than staying on top.
• Too much liquid: There are supposed to be four eggs per 1/2c of liquid. Maybe if I use 2c of liquid, I need 12 eggs?
• Pasteurized juice: I used fresh lemons for the lemon bars, and fresh limes for the lime bars. Maybe pasteurized grape juice is missing important enzymes?
• Acidity: Grape juice is way less acid than lemons, and the lime bars have one part lemon to six parts lime. Maybe that matters? I can try half grape and half lemon…
• Sugar: The lemon and lime bars call for 2c of granulated sugar. I left that out because the grape juice is so much sweeter than lemon or lime. Maybe I needed those crystals?

My test audience (gamers will eat anything) seemed to quite like it. One even asked for seconds! So I will probably try this one again, especially since it lands me with half a batch of peanut butter cookies even if the recipe itself is an epic failure. (I also bought 100% cranberry juice, which I will certainly use the sugar with, and probably cut with fresh lemon juice. I will also not put that over peanut butter. Ew.)