What is this? Mustard greens?

So, this thing is growing like crazy,  to the point it's in bloom.
I'm sure I planted it at some point,  but I'm not sure what it is.
What do you think?

Looks similar to the mustard green variety that I grow. It's good as a cooking green.

Flowers definitely looks like mustard, but the leaves seem a bit off. Have you tried tasting one of the leaf ? You might need to do it several time if you don't taste anything, but if it taste a bit spicy it should be mustard.

If you wait a while, it should go to seed and look even easier to recognize.