uh oh

November 22, 2012 11:29 AM

11th hour baking question: Can i Substitute gelatin for cornstarch?

I'm making this recipe:
http://smittenkitchen.com/blog/2009/02/whole-lemon-tart/
And I don't have cornstarch. Can I substitute knox unflavored gelatin? If so, how much? Any special preparation?

posted by pintapicasso to food & drink (5 answers total)

You can generally substitute 2x flour for cornstarch - so for that recipe I'd use 4 tbl of flour.
posted by muddgirl at 11:34 AM on November 22, 2012 [1 favorite]

I've made this recipe before -- it is one of my go-tos (I hope you use the crust she recommends, it is amazing) -- I definitely would not use gelatin, I typically use tapioca but I agree that the 2x flour is a better way to go. Good luck!
posted by hrj at 11:59 AM on November 22, 2012

i've made it too, and i also would not recommend gelatin. What other flours do you have on hand? According to the Joy of Baking, substitutes for 1 tbsp of corstarch are:
2 tablespoons (25 grams) all purpose flour
1 tablespoon (15 grams) potato starch or rice starch or flour
1 tablespoon (15 grams) arrowroot
2 tablespoons (25 grams) quick-cooking (instant) tapioca
posted by Kololo at 5:54 PM on November 22, 2012 [3 favorites]

Update: I substituted 4tbl all purpose flour and it came out horrible! I ended up scrapping the whole thing. However, I'm 99% certain the flour wasn't the culprit and something else ruined it. The filling was curdled, the top of the tart was overcooked but the middle was liquid. Additionally it was way too bitter (I did not use a meyer lemon.) I want to make it again but I'm at a loss.

Silver lining: I did make the crust she recommends and it came out great, no problems there.

(and luckily, I also made a s'mores pie which was AMAZING)
posted by pintapicasso at 4:38 PM on November 23, 2012

The bitterness is from the lemon rind/pith on a non-Meyer lemon. It looks like Meyer lemons have a much thinner peel and are sweeter overall. Other recipes for lemon tarts/curds I've seen call for the rind of 1 regular lemon and the juice of 3 lemons (or thereabouts).

You might also try cooking this in a water bath? I don't know if that would be enough to even out the custard cooking. I would also consider cutting the amount of butter at least in half (other lemon tart recipes call for closer to 2-4 tbl butter) and seeing if that helped the curdling/setting problem.

I don't know if all these substitutions are worth it considering there are other lemon tart recipes out there.
posted by muddgirl at 5:35 PM on November 23, 2012