Heat the frying oil in a frying pan over medium-high heat; ensuring there is enough oil to cover plantains. Let the oil reach 350 degrees.
Peel the green bananas using a pairing knife. Cut the peeled plantain into 2 inch thick pieces. Ideally you have 3-4 pieces per plantain.
Fry the plantains in the hot oil until lightly browned, about 5 minutes, remove them from the oil and place them on paper towel to drain excess oil.
Place a piece of parchment on the bottom of your lemon squeezer or tostonera, then place the plantain piece in the lemon squeezer and cover with another piece of parchment paper.
Squeeze down on the lemon squeezer until you have a small cup shape. Remove the toston cup carefully and place on paper towel lined plate.
Fry the cute little cups for a second time in the hot oil until golden brown then place them on a plate with napkins to drain the oil and sprinkle with a little salt.
Fill the tostone cups with your favorite filling
Serve immediately.