I made this as a filling for a 4-layer cake stuffed w/bananas. After I finished cooking it, I wasn't happy. BUT the final step of mounting the butter and beating it made all the difference...changed it from 'bad rubbery pudding' into a delicious cake filling. Definitely worth the time to make. (Changed one thing; I used a double boiler to cook it to avoid the crust that sometimes forms when heating custards.)
4 tablespoons cornstarch CUT INTO PIECES?? Yet another mistake. Again... Martha! You need better editors. I'm constantly finding errors! Very frustrating.