Put the lentils in a pot and cover with water. Bring to a high boil then decrease heat to low, add bouillon and simmer on low for about an hour until lentils are done. Either cook out all of the liquid or drain them.
When lentils are done and drained, add them to a mixing or salad bowl. Add the onion and garlic and set aside.
In a skillet, add the olive oil. Once heated, add the frozen vegetables and cook for about 5-7 minutes until they are cooked through.
Once done, add to the bowl with the lentils. Mix together and add salt and pepper (if needed) to taste.