The PURPOSE of a "bain-marie!"
You can also improvise a bain marie. How? Simmer a pan of water and place a stainless steel bowl over the pan. Fill the bowl with the food that is about to be cooked. Which is better: to buy a tradition bain marie or improvise? Improvise. Yes, I have a traditional bain marie stainless steel clad construction pot that my grandmother gave me. But I almost always improvise. Why? Most people have a stainless steel bowl and pan in their kitchen. Don't waste more money on ANOTHER pan you have to put in your kitchen.
How to make your own person bain marie:
1) In a medium size sauce pan (about 3-4 quarts), fill half way with water.
2) Put it on medium-high heat. Let boil. Turn heat down to medium, thus the water is at a simmer.
3)Put your ingredients in a stainless steel (NOT plastic or glass! Stainless steel can take high heat VERY WELL!). Place the bowl over the pot of simmer water. Using your kitchen utensils, stir until cooked/thickened. (You may choose to wear an oven mit during this process, the steam is very hot!)
4) Remove bowl, be careful of the steam. Turn off the stove top.
Why a bain marie? It "cooks" food gently and softly. It is meant for food that, when exposed to direct heat, will scorch or burn.
A bain marie is keeps food nice and hot! Think: those fancy chauffer dishes for buffet dinners.
Most popular foods that need to be cooked in a bain marie:
-Custards, like creme brulee
-Hollindaise sauce, for eggs benedict
-Warm milk, like for baby's forumla
-Charcuterie items, like pate and terrines
Most people do not use a bain marie ENOUGH to buy a tradition bain marie. Just improvise and get cooking! Remember, the steam that is released is very hot and dangerous. I like wearing an oven mit when I am cooking food over a bain marie.