Preheat the oven to 400 degrees F (200 degrees C). Line a baking sheet with foil. Spray the foil with non-stick cooking spray.
Combine chopped turnip, carrots, olive oil, lemon pepper, and salt in a large bowl. Toss until well combined and lemon pepper has dissolved. Spread vegetable mixture on the prepared baking sheet in an even layer.
Roast in the preheated oven for 30 minutes. Stir and roast until vegetables are soft, about 15 minutes more.