Totally accidentally shilling for SE right now, but I learned a bunch of really cool tricks for cookies from an analysis about the different variables in cookies [1] that basically let me basically "build" my own secret recipe. Stuff like browning the butter before mixing it into the dough, resting dough overnight, using precise mixes of egg/flour, using chopped chocolate instead of chips, etc.
Kenji López-Alt alt has a really good book too called Food Lab, taught me all about sous vide in a cooler (which led me down the road to making steaks that are better than you get at a restaurant every single night).
Agreed, that book is great. I keep pushing off getting a real sous vide setup because the cooler is 'good enough'.
Last year I went to a fancy steak house in Las Vegas, and my thought was that I prefer my own steak. I was surprised, since I assume that restaurants have access to better cuts and can age it better. I mean, it was a fine steak, but I preferred my own.
I have been a firm believer in my own steaks for a number of years since I got my Big Green Egg. Picked up a sous vide circulator in January and it is AMAZING!
I have a BGE as well! I got the steel plate-setter for searing and it's incredible. But TBH, I often just use a skillet and our stovetop for finishing.
[1] https://sweets.seriouseats.com/2013/12/the-food-lab-the-best...