I have found that I cook the fastest when I prep all the ingredients beforehand and have everything ready to go before I light the stove.
Earlier, I tried to do things in parallel. I often lit the stove and sauteed the onions while I prepped the other veggies, assuming that this multi-tasking would speed up my cooking. Alas, this strategy backfired. In my attempt to do everything at once, I would forget some key step, and would have to invest time and effort in making up for the lapse. Also, like a car’s body that has been tinkered, the dish won’t taste as good. Therefore, I ended up taking longer to cook a meal that is partially burnt or badly flavoured.
When we multi-task, we are often blind to how we need to scramble to fix things later. The recipe to fall behind schedule and get results that are sub-optimal is to do several things at once.