Went here, on my host's recommendation, for a comida corrida near the house.
A comida corrida is a light, multi course meal, served in the afternoon. There may or may not be any choice. Typically there's a drink (with refills), soup, main course, dessert. The menu varies from day to day. Occasionally an appetizer. They're cheap. When I spent the summer of 2007 in Oaxaca in a working class district. I ate many a comida corrida. Prices were 25-35 pesos. In the tourist areas they would be higher, sometimes 80 pesos.
Mama Elena is in a popular area near the cathedral but the price was only 50 pesos. I ate here twice. Once it was late and I got the tacos dorados. They were good. The 2nd time was for the comida corrida. The soup was OK. This day the main was fish. It was perfectly cooked. Salad completely fresh. The banana with yogurt (?) and granola (?): a very refreshing end to the meal.
Service was quick and friendly. An excellent deal. 4 * because there's simply an upper bound on comidas corridas. At least, in my experience.
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Notes: (1) the entrance is actually on Calle de M Bravo and is very easy to miss because ... (2) this is a true hole-in-the-wall with few tables. If there's an open seat at a table already occupied you can take it. I saw this. read more