Cake or Death? and posted on her site, calls for caramelized apples and apple butter, but I still had about 4 pounds of rhubarb in the fridge, so that's what I used.
I roasted some stalks of rhubarb and a vanilla been, all sprinkled with sugar in a 375℉ oven for 15 minutes or so. This resulted in tender but not falling apart rhubarb and a beautiful pink syrup speckled with vanilla seeds. I used this rhubarb in between the layers of bread in the pudding. To replace the apple butter, I cooked some sliced rhubarb with sugar, cardamom pods, a vanilla bean and a bit of water until it fell apart. I then reduced it until it was very thick and spreadable. I spread this on the bread and it was delicious--you could really taste the cardamom.
I only made 2 ramekins of the bread pudding, as it's not one of my favourite desserts, but I regretted this as soon as I tasted it. It may look a bit schlumpy and unappealing, but this was fantastic! Rhubarb and custard are a perfect match, and mine was really custardy. Here's a photo I snapped as I was eating the second one, minutes after finishing the first. Yes, it's a bit blurry, but I wanted to eat it before it cooled off. Notice I didn't bother with the sauce and roasted rhubarb garnish the second time around.
I have also made rhubarb soda, rhubarb tarts and rhubarb fool/pavlova with my mountain of rhubarb, but the pictures are stuck on a camera that stubbornly refuses to turn on. I'll post those, and the other rhubarb desserts I have in mind when I can figure out how to get the pictures.