Rosia uses her bare hands to flip the blue corn tortillas toasting on the grill in front of her. She looks up when a passing man shouts out a friendly tease and says to him in Spanish, "I know where you live!" then smiles at us sweetly. She plates three quesadillas: papas y chorizo, hongos (mushroom) and flor de calabaza (squash blossom). My friend holds out some cash and she puts on a plastic glove before touching the bills. It's endearing, this nod to cleanliness, standing in front of a grill-topped cart next to a grimy alley in Echo Park. Rosia smiles sweetly again when we thank her for the food. I think I want her to adopt me, especially after I taste the quesadillas. Her cart, parked just south of Sunset on Echo Park Avenue, serves only quesadillas. But save your chicken quesadilla craving for another day and instead order the flor de calabaza, delicately chewy and tasting faintly of squash, or if you're feeling brave, huitlacoche (corn fungus). The blue corn tortillas are made to order, the handful of dark masa flattened and grilled before you know it, and the condiments include cotija cheese and nopales, strips of cactus tossed with cilantro and onion. There's a fruit man just a few steps away, should you want to make it a nutritionally complete meal, and the Salina's Churros truck often stops at the end of the block. You'll have to seat yourself on a curb in the nearby parking lot to eat your food, but it may be one of the finest three-course meals for under $10 in the city.