First off, thank you everyone who replied. To give a little more backstory, I wanted to clean out my freezer and there was a bag of blueberries from 2010 and two boxes of puff pastry I never used for a separate project. After posting here I discovered a
Vol-Au-Vent recipe on Pepperidge Farms' website--the puff pastry was of the same brand so I figured, why not!?
So... they're... pretty bad actually. I learned a lot making these. I do cupcakes/cakes/cookies all the time but very rarely stray into the land of pastry except for when I make pies (I'd like to think I have the best pie crust recipe).
Things I Learned:
1.) Eat the puff pastry right away. RIGHT AWAY. I put them in an airtight container and the next day they were no longer light and fluffy but kinda... stiff and chewy?
2.) Don't be afraid to boil things longer. Both the blueberry sauce and the custard were ridiculously runny. Partially because I always second-guess myself and also because my mother hovers over me in the kitchen arguing with me, "You're gonna burn it!" so I either turn the burners down or just turn it off when it's "boiled enough". Lesson learned. KEEP GOING.
3.) Eat them the day of. Maybe just an addendum for #1, but, well... Now, truthfully, all that sugar guarantees they don't taste BAD per se... it's just all the textures are wrong, hahaha.
So there you have it. I definitely want to try making pastries again, but... just need to learn from my mistakes. ;)