I am testing a butterscotch pudding recipe and I love the flavor except for a lingering starch flavor/texture I get at the end. I remade it today and stirred it at a simmer for 2 1/2 minutes, but I still notice the starch. The ratio of starch seems fine, because it isn't as thick as pastry cream. What am I missing? 2 1/2 minutes at a simmer should be long enough.