Fire is typically a poor heat source for direct cooking. It fluctuates with every breeze so the heating is very erratic. It also produces a lot of soot which tastes terrible and is bad for you.
When cooking on a campfire much better results are had by cooking next to the coals than above the flame. Cooking with a gas flame is more reliable of course.
A couple direct cooking applications of fire in the kitchen, that I can think of are:
- Flambe: Lighting a sauce which contains a lot of alcohol to burn off some of the raw alcohol taste.
- Roasting: Putting a steaming basket over a gas flame and charring the skin of peppers or eggplant.
- Caramelizing: Using a blowtorch to put a crust on creme brulee or to sear the exterior of a sous vide steak.
I would recommend starting with the blowtorch for several reasons:
- It is harder to burn your house down with a torch than with a pan of flame.
- Blow torches are useful for things outside of the kitchen like stripping paint or starting the grill.
- There is something deeply satisfying about wielding a hissing, blue, knife of fire that appeals to the caveman within.
As for safety. Keep a fire extinguisher on hand. Don't let kids or pets in the kitchen when you are playing with fire. Keep your home owner's insurance current.