How to make a small DIY bain marie? I live alone and almost always cook just for myself. With most recipes, I can just cook a smaller amount than given in the recipe, and I have optimized most of my cooking gear for small quantities. But I have a problem with some dishes which are both too rich to eat more than one, maximum two portions in a day, and too perishable to store for longer. Some of those, like the egg foams (zabaglione, hollandaise) and some sweet dishes involving melted chocolate, require a bain marie. 

I don't have the storage space for single-purpose gear. When I need bain marie, I use a regular pot and a Pyrex bowl whose upper diameter is somewhat bigger than the pot's. My smallest pot is 16 cm, and a bowl which fits on it is too big for one or two yolks. When I try beating them, they smear themselves on the walls and cook there before they've flowed to the bottom. Also, the heating is somewhat quick, because the whole mass is only 1 cm thick or less. Making 40 g ganache is no easier. 

I prefer beating such small amounts in a tea cup or mug or in a 6 cm bowl, inserting a single beater into the mixer. But I cannot do it when I need a bain marie, because I have no pot where they'd stay on top. And even if I could find a small replacement for the pot (like a steel mug or a djezwe), it won't heat on my induction hob - even if the "pot" was ferromagnetic, the hob  has a built-in protection and only switches on if it detects a cooking vessel at least 12 cm wide. 

Do you have any ideas for an easily built bain marie setup which is small, uses common utensils (not necessary kitchen ones, but preferably something I already have), and quickly dismantled when not in use? Maybe there is some way to suspend the tea cup into the big pot and hold it firm despite the mixer's force?
Can you repurpose a stovetop coffee pot/percolator?  I prefer the glass ones (do an image search for 'coffee percolator glass', so you can keep an eye on progress throughout.  If you were to replace the drip container at the top (that usually holds the coffee) with a small stainless steel bowl (your standard IKEA type mixing bowl), the rim will be held stable by the coffee pot. 

Plus it already has a handle built in so you don't burn yourself in search of the perfect chocolate ganache!  

ps: I'm in Germany too - I saw some at Tchibo last week.