Like PaulM states above, vla is a Dutch dairy dessert. In the Netherlands, it's available in every single supermarket, a basic household necessity. Vla is very similar to custard, but made with different thickening agents and available in many flavours. You won't find this in any restaurant though, it's much too ordinary for that.
Vla used to be a standard dessert when I was still living with my mom and dad. Every day we'd have either vla or yoghurt after dinner, never vla two days in a row because yoghurt is much healthier... I think the reasoning behind this was the sugar content in vla, but as we always added sugar to yoghurt as well, I'm not sure how sound that argument is. Back then, vla was available in vanilla, chocolate, white (blanke vla, the word white is the same here as is used for 'white' people), hopjes (hopjes are a butterscotch-like coffee candy) and raspberry, which tasted mostly chemical and extremely sweet. When I was home alone I'd drink vla straight from the container, a very serious sin as far as my mother was concerned. I still like to do this because it still gives me the feeling of being gloriously naughty.
An extra special treat would be a vlaflip. This dessert was made up in the 1960s when vla had become old-fashioned, to jazz it up a bit for the youngsters of that time. A vlaflip consists of vla (usually vanilla), plain yoghurt and a splash of fruit syrup, preferrably red. Perfect food when you are sick.
Nowadays vla comes in many more flavours. There are seasonal varieties, combination containers (chocolate and vanilla in one container, do not shake!), there is vla with pieces of brownie, vla with tiny chocolate balls... you name it, somebody thought of it. Even the vlaflip is now available ready-made. Buying it that way however deprives you of the pleasure of pouring out of two containers at once and determining your own vla-to-yoghurt-to-syrup ratio. Although some of these new types of vla are rather tasty, I prefer simple vanilla, to which you can simply add your own ingredients to make it even better: banana, cinnamon, chocolate sprinkles.... Mmm. | 
