Gather all ingredients.
Blend carrots in a blender until smooth. Add beets and blend until smooth.
Heat oil in a skillet over medium heat. Add onion and garlic; cook and stir until onion is translucent, about 5 minutes.
Stir in puréed vegetables, vinegar, Italian seasoning, and bay leaf; cover and bring to a boil. Uncover, reduce the heat to low, and simmer for at least 30 minutes, or up to 4 hours.
