Pour the tomato sauce into the bottom of a small oven-safe dish (I used a 6–inch round). Place the feta in the center and press to slightly break the block apart. This is a rough-crumbly-spreading situation, not a make-a-clean-cheese-layer situation.
In a medium bowl, mix the olives, tomatoes, garlic, oregano, and pepper — you don't need to season with salt, as the feta is salty enough on its own. Pour the mixture evenly over the cheese.
Bake for 15 minutes. Your kitchen will smell like pizza and the feta will get warm and spreadable. Top with the parsley once it's out of the oven.
Serve to guests with toast or crackers, or stuff into a pita pocket with a fried egg and arugula for a meal for yourself.