Impossible pies are so called because it's impossible to believe that such a large quantity of very sloppy cake batter could ever cook into something edible. However, while baking, the mixture separates into layers - a thin dense bottom crust that is very much like pastry, with a custard like layer in the middle that gradually changes to a lighter airy sponge on top. When the impossible pie is a coconut pie, the top becomes golden and crunchy, which is a good contrast to the moist custard layer below.
a recipe taken from Sue Lawrence's book 'On Baking', which just mixes all the ingredients together and pours them into a large pie dish before baking for 50 minutes. Some recipes make things a little more complicated by whisking the egg whites separately and folding them into the batter.
I really didn't expect my husband to like this, as he's doesn't usually like anything that even hints of custard, but he surprised me by saying he thought it was quite good! Perhaps it was the coconut that won him over!
This was so quick and easy to make, using ingredients that any baker keeps to hand, that I think I'll be investigating other recipes for impossible pie soon - I've heard there's a chocolate version!
In the photos of the cut pie, I think you can see how the custard layer gradually becomes lighter and spongy as you get towards the top.