Saving Soupy Pastry Cream?
I've never made pastry cream before, but wanted to make some fresh fruit tarts, so I tried the recipe in my cookbook--essentially half-and-half mixed with sugar on the stove, whisk together egg yolks, a little more sugar and some cornstarch in a separate bowl. Add a little of the hot half-and-half to the yolks to temper, then mix it all up on the stove, cook until it gets bubbly on top, remove from heat, add butter and vanilla, and refrigerate until pudding-like.
Except I screwed it up. First of all, without even thinking of the consequences, I substituted evaporated nonfat milk for the half-and-half, because I ALWAYS substitute that for half-and-half or cream. I've been cooking reduced-fat for so many years I don't even think about it anymore. Which I'm sure was a mistake. And secondly, I didn't cook it long enough when mixed, I think, because the butter took a little time to melt, which seemed odd when added to hot sugar and milk.
So now I have sweet milky soup that never congealed. Can this be saved? I was thinking of baking it like a custard in a water bath or something...But I don't want it to turn gummy. Thoughts?
i don't see where the evaporated milk would affect the way it cooked up. it just sounds like you didn't cook it long enough. if you do it right, while its on the stove you will see the mixture obviously start thickening just before it starts boiling. After you see the first bubble start to burst (its boiling) keep whisking/cooking it for about another minute or so to make sure the starches get cooked out and to make sure that the mix has reached its full thickened capacity. but don't cook it much further than that because there is a point where it can get to hot and almost kill the starch, resulting in a goopy mess. the key is to whisk constantly on the heat (about medium heat) so you make sure that there arent any lumps or curdled parts. also, some creams are finicky when you add the butter at the end, so if you add all the butter too fast, the emulsion breaks a bit, leaving you with a runny mix. there are so many factors that can affect a recipe! you could try cooking it on the stove again to see if it will thicken (if you're unsure, you can always add another egg yolk to make sure). i'm not sure if cooking it in a water bath would work because you've already got butter in it, which might act funny when you bake it hope this helps! and using regular milk would work a bit better, for future reference. i've used lowfat milk and even soy milk in recipes like these and it works!
The reason that your pastry cream did not thicken is either there is not enough cornstarch or you didn't bring the mixture up to a boil. Unlike flour, cornstarch works quickly and does not much cooking...just up to a boil. Cooking it longer might thin out the mixture.
Put the thin pastry cream back over medium heat and bring it up to a boil, whisking and scraping so it does not scorch to check if it will thicken. If not, whisk together couple tablespoons of cornstarch and a little cold milk. With the pastry cream still cooking, whisk in the cornstarch mixture, a little at a time, until the pastry cream thicken to the desire consistency. You might not need to use all the cornstarch mixture. If the chilled pastry cream is too thick, whisk in a little cold milk.