- 1/4 cup minced white onion
- 2 tablespoons unsalted butter
- 1/2 lb mushrooms, trimmed
- 2 teaspoons chopped freshepazote leaves, or 1/2teaspoon crumbled dried
- 1/4 teaspoon salt, or to taste
- 2 cups masa harina (“masa mix”) such as Maseca or Quaker
- 1/2 teaspoon salt
- 1 1/3 cups warm water
- 5 oz queso fresco (Mexican fresh cheese), ricotta salata, or feta, crumbled (1 cup)
- 1/4 cup Mexican crema or crème fraîche (omit if using ricotta salata)
- 5 squash blossoms, petals torn into 20 pieces and remainder discarded
- About 3 cups vegetable oil
- Accompaniment: guacamole
- Special equipment: a tortilla press or a rolling pin; a deep-fat thermometer
- Cook onion in butter in a medium nonstick skillet over moderately low heat, stirring, until softened.
- Pulse mushrooms in a food processor until coarsely chopped and add to onion along with epazote and salt.
- Cook over moderate heat, stirring, until mushrooms are softened and any liquid is evaporated, about 7 minutes. Remove from heat and cool filling completely.
- Stir together masa harina, salt, and warm water in a large bowl with a wooden spoon until it forms a dough. Knead dough in bowl with heel of your hand 1 to 2 minutes.
- Pinch off small pieces of dough and roll into about 40 (scant 1-inch) balls. Transfer balls as formed to a plastic-wrap–lined tray and cover with more plastic wrap.
- Cut 2 (5-inch) squares from a small plastic bag and use 1 to line lower half of tortilla press. Put a ball of dough in tortilla press and top with second square of plastic. Close tortilla press, pushing gently on lever to flatten dough to a 2 1/2- to 3-inch round. If press doesn’t flatten evenly, rotate tortilla 180 degrees and gently flatten again. (Alternatively, use rolling pin to flatten dough between squares of plastic.)
- Remove top square of plastic and put 1 teaspoon mushroom filling, or about 1 teaspoon crumbled queso fresco with 1/2 teaspoon crema and a piece of squash blossom, in center of round.
- Fold round, still in plastic, over filling to form a half-moon and pinch edges together to seal. Gently peel off plastic, then transfer quesadilla to another plastic-wrap–lined tray and cover with a second sheet of plastic wrap. Repeat with remaining dough, making about 20 quesadillas of each filling.
- Heat 1 inch of oil in a deep 10-inch heavy skillet over moderately high heat until deep-fat thermometer registers 375°F, then deep-fry quesadillas in batches of 6 to 8, turning once or twice, until golden, about 4 minutes. Transfer with a slotted spoon to paper towels to drain and return oil to 375°F before adding next batch.
- Serve quesadillas immediately.