I can eat my custard hot or cold but my family likes it best cold.
I say the grated choc is optional as in reality it probably doesn't really need it but I put it in any way for a bit of extra chocolate ooomphf
I don't know why but sometimes it gets a very fine skin, personally it doesn't bother us we just stir it in. If you are worried, then when you pour the custard into the bowl let cool for a few minutes and fit cling wrap to the top of the custard right to the edges of the bowl then in the fridge.
If you think you have lumps pour custard from the pot through a strainer into a bowl.
If you like a thinner custard add a little more milk.
If you'd like custard a little thicker take a little milk away.
Yes you can do in the microwave, heat and stir in 1 minute bursts. (heat stir, heat stir, etc) Until just bubbles.
This is good poured over a slightly dry cake.
Lovely cold with sliced cantaloupe, banana, pears or peaches.
This keeps in the fridge for a day or two but this make enough for 4 of us with fruit or a pudding slice and it goes in one sitting.
This photo was taken after I whisked the skin back in when cold, you don't really notice it, if anything it looks like tiny flecks of chocolate.