I am not fond of cornstarch as a thickener. It works, for sure. But there’s something glutinous about the way it thickens that I don’t like. I prefer flour which thickens in a grainier way. Well, I don’t think that word captures it very well, but it’s all I can come up with.
Thickening is a tricky business, because you don’t want to go too far and have your pie taste store-bought. All store-bought pies use cornstarch as a thickener, and they just become treacly, I think.
You want something (or I want something) that thickens while still leaving the fruit as the star of the pie. Sometimes you can use the crust as a way compensating. Maybe put a little sugar in, but better yet, some ground almonds. You may want to use European butter in the crust—if you make butter crust.
But, aside from the challenge from your mother, I’d rather have runny pie than cornstarch in it.
The custard method is something I’ve tried on occasion. I’ve used an egg and cream cheese in the mixture. If it’s apples, I use some port, too. I’m not sure I’d use port in the rhubarb pie, but there might be some other liquor—maybe an orange liquor—that would fit. Yeah, I think Grands Marnier or Triple Sec would go well in a strawberry rhubarb pie.
I think I used the egg-port-cream cheese thing in the “best pie ever” I made once. This compliment came from a good cook, too, so I was a bit shocked. But I’ve stopped using it for the moment. Going back to basics. Which works, too.
Our strawberry and rhubarb season is a month over, now. It lasted maybe three or four weeks. Those seasons go by so fast. Blink, and they’re gone. But I love those local strawberries that seem to concentrate strawberryness into a tart art. They go bad in two days, so you’ve got to use them instantly. You can put them in the fridge, but they change and get dampened, somehow.
Anyway, one for your mouth and two for your pie. Sugar it for sweet or tart—really isn’t a bad idea to be spare on the sugar. Depends on your taste of course. But set a rhubarb pie in front of guests, and you can see their mouths drop and the saliva drip onto the tablecloth. It is one of the most rewarding experiences a cook can have.