Heat the oil in a wide skillet over medium-high. Add the beef in one layer and leave it alone for 4 to 5 minutes, until the underside is deeply browned.
Break it up and brown the other side, then push it to one side of the pan.
Add the onion and carrot to the cleared space and cook 5 minutes, until softened at the edges.
Stir in the garlic, cumin and oregano and cook 30 seconds, just until they smell toasted.
Add the diced potato, tomatoes, tomato sauce, broth and salt. Stir everything together and bring to a simmer.
Cover and cook 15 minutes, then uncover and cook 10 minutes more, until the potato is tender and the liquid has reduced to a thick sauce that clings.
Taste for salt. Serve hot, in tacos, over rice, or as a filling.