Andre Santos, senior artist, BioWare
It's pretty difficult to fill every nook in the game with interesting content or loot, so sometimes the best reward we can offer is a silly visual treat. Starting in Dragon Age II, the environment artists hid large numbers of cheese wheels and slices all over the game. Typically, we like to hide cheese in places that are off the beaten path, but sometimes it's just blatantly obvious.

In the Temple of Mythal, there's a Pac-Man reference made out of cheese wheels. It will take a keen eye to spot this one in the courtyard because it's mostly covered up by Ivy.
Additionally, there's a failed cheese-summoning ritual midway through the temple. It will be pretty dark, so make sure you bring someone who can cast a bit of light.
The Storm Coast had a cheese boat crash into one of the basalt columns in the water. You'll have to use some unorthodox means to get to this one, but you'll know it when you see it. While on your way to the boat, you might want to check out the three statues in the treasure room—they have some cheesy surprises.
Lastly, if you are in Crestwood, you shouldn't have too hard a time finding cheese in odd locations. Leave no stone unturned.