It is the Spanish version of an English egg custard, but is a lot thicker and richer. It is very easy to cook, only taking 9 minutes in the microwave. It is served in a lot of restaurants, topped with fruit and cream, Even better just eat it as it comes.
The quesillo in the below picture is the large version and you need to double the quantities and cook 0n 580w for 30 minutes and leave for 10 minutes to stand. If it is not cooked at this stage put it in the microwave for an extra 5 minutes.
Mix by hand - you are trying to achieve a smooth quesillo, so try and not get too much air into the mixture when blending, if too much air gets into the mixture at the blending stage, the quesillo will have air pockets (holes). This only spoils the looks not the taste. Leave to cool before tipping out onto a plate, it will be a lot more successful. When cooked it will start slightly shrinking from the edge of the dish.
I needed to cook mine a little longer. My microwave is 800w so I put it on 50%power for ten mins but it was liquid so I then gave it a 3 minute blast on 80% but it still was a bit wobbly so I blasted it on full power for two mins but kept a close eye on it. I thought it would boil over but it didn't. Tasted fab but very very sweet so a little goes a long way. Next time I'd probably cook it for two minutes more on full power as it was still a little wobbly. - 22 Nov 2015