what is the secret to thick buttertart filling????

Answer 1

I was a former chef in Canada and seeing as most Americans do not know what a butter tart is I assume your from Canada.

I use both sugar and corn syrup, a touch of flour and egg yolks instead of whole eggs, I like lots of raisins and walnuts (I am partial to them to), and real butter for the filling, I don't bother making pastry, you can buy shells at M&M Meats.

I find to if you bake them at 350 for 40-45 minutes, and if they puff don't worry, they will come back down.

Answer 2

My guess would be gelatin.