Peel the green plantains by cutting off both ends, making a shallow slit along one of the ridges, and using a paring knife to pry off the skin. Cut each plantain into 1-inch thick rounds.

If using garlic water, dissolve salt in water with smashed garlic cloves and set aside.

Heat vegetable oil in a large heavy skillet or deep pan over medium heat to about 325°F (165°C). The oil should be about 1 inch deep.

Fry the plantain rounds for about 2-3 minutes per side until lightly golden but not fully cooked through. Remove with a slotted spoon and drain on paper towels.

While still warm, flatten each piece using a tostonera or the flat bottom of a glass to about ¼-inch thickness.

If using garlic water, briefly dip each flattened plantain in the salted garlic water.

Increase oil temperature to 375°F (190°C). Fry the flattened tostones for 2-3 minutes per side until golden brown and crispy.

Remove from oil, drain on paper towels, and season immediately with salt while still hot. Serve right away.