Flan Nature - anybody got a good recipe?

[WildflowerMarmalade]

Does anybody have a good, reliable recipe for Flan Nature, the kind you get in France?

I tried this recipe from The Guardian which didn't turn out too well. All the flour sank to the bottom. It didn't separate but I didn't end up with that lovely, smooth, solid custard effect. It's also a bit sweet for my taste.

Things I may have done wrong include: using cornflour (recipe doesn't specify so I guessed), the oven being too hot (I didn't really adjust for our fan oven), I beat in the flour, milk etc rather than lightly whisking.

Would anyone be kind enough to share their recipe? Or let me know where I could be going wrong?