Okay, it happened again. The recipe said turn the heat to medium high and watch your veggies brown - takes 15-20 min. I did everything exactly the way the recipe said: heavy (cast iron) dutch oven, olive oil, medium high heat, frequent stirring - and what do I get? Beginnings of a burn, not a brown, in about 5 minutes. I turn the gas way down, take it much more slowly and manage to salvage the dish. This happens to me all the time. The temp suggestions and the predicted time to accomplish whatever - browning, softening, caramelizing - are so far from my reality! What am I doing wrong?