Adapted from
Cooking for Jeffrey by Ina Garten
Some of you may be wondering about canned pumpkin puree. The canned pumpkin puree you buy is either made of pumpkin or a dense type of squash that resembles pumpkin. It's good for baking as it has less water and fiber than other types of pumpkin or squash. (It's different than canned pumpkin pie filling, which is sweetened and spiced. Don't use that.) It's very convenient but if you want to
make your own pumpkin puree, you can find instructions on the internet where to do that, or you probably already know.
Two things to look out for: Be sure to cook the syrup to 230ºF (110ºC), and watch it carefully. If you overdo it, add a tablespoon or two of water to lower the temperature and cook it back again to 230ºF (110ºC).
The second is that I goofed up with the original quantities of ingredients and used a whole can (about 1 1/2 cups) of pumpkin puree, rather than the 1 cup that was called for. It was delicious (and I didn't have to worry about what to do with 1/2 cup of leftover pumpkin puree...) but it made enough custard to fill my 8-inch (20cm) round pan right to the very top, so some of it sloshed out and was a bit messy to slide in the oven.
If you want to use the entire can, I would fill the round pan to about 1/2-inch (1,5 cm) from the top and bake extra custard in a ramekin or custard cup alongside the flan until barely set, and have it for a little baker's snack.