1. In a large pot over medium high heat, boil the potatoes and the carrots until tender, about 15- 20 minutes. After about 10 minutes of cooking, add the eggs to the pot to boil the eggs with the potatoes and carrots until cooked. Remove from the heat and discard the boiling water. Let cool.
3. Cut the cooled potatoes, carrots and eggs into cubes. Place it all in a large mixing bowl. Add the peas, corn, reserved onion, beets and mayonnaise. Mix to combine well. To make the ensalada mixta, omit adding the beets.