Slice the carrots into thin ribbons. Bring a a saucepan of water to the boil. Add the carrots and blanch 15 seconds and drain.
Combine vinegar and olive oil in a bowl. Squeeze in the roasted garlic. Whisk in oregano, salt and pepper. Add onion and stir. Add carrots and lentils, while still warm, and parsley. Let sit for 10 minutes and serve.