Cut potatoes: Wash and clean the potatoes very well. You can leave them unpeeled, but make sure they are very clean. Halve or cut them into thick slices, depending on size.
Saute: Chop the onion finely. Heat the oil in a large cast-iron skillet or a non-stick pan. Cook the onions on medium-low heat until translucent.
Add the potatoes and the tomato paste, stir well and cook them for about 2 minutes, stirring often.
Simmer: Add tomato sauce and vegetable broth, some salt, and pepper. Mix well, turn the heat to low, and cover the pot leaving a small crack open. Cook for about 20-25 minutes, stirring several times in between until the potatoes are tender. Add a little bit more vegetable broth if the dish becomes too dry; I added about half a cup more vegetable broth.
Finish: Grate the garlic cloves, add them to the skillet, stir well and cook for further 2 minutes. Serve hot.
Regular potatoes can be substituted. Cut them into chunks.