Agustin Juarez estimates that on an average weekend, 500 pounds of menudo is consumed by the patrons of Los Alamos Market y Cocina. That's a lot of cow stomach. But they don't mess around on the West Side. And they obviously don't go to Juarez's windowless brick convenience store at 17th Street and Summit just to buy cigarettes and Jarritos, either. Past the rows of sundry goods (paper towels, pop, canned soup) and not far from the beer refrigerator (under a colorful mural that includes the phrase "Cerveza Time") is a small kitchen that produces some of the best made-from-scratch, authentic Mexican food in town. From the chorizo and huevosrancheros at breakfast to the posole and carneasada at dinnertime, the place emanates smells that make the gut growl with lust all week. And it's all made by two women: One gave birth to Juarez, and the other married him and co-owns the store. Come in at the right time, and you might catch Juarez himself peeling piles of tomatillos for the boss ladies to make into a hearty salsa. They don't mess around at Los Alamos.