How do I make a bloom effect?

There is a way to achieve something like that?

The light in the background isn't just with some glow.. it surpass the sprites in front of it and make a nice lighting effect.

Just putting an almost transparent yellow sprite in front of the mountains would achieve the same effect, without an expensive Effect.

Hehe thank you for the answer!

But I would prefer something more "dynamic".. like an effect or something like this.