Rinse shrimps and defrost at room temperature for 1-1 1/2 hours. Peel prawns, except for the tail fin, and remove the intestines. Wash shrimps and pat dry. Peel and slice the garlic.
Heat the oil in a pan. Add the prawns and fry them for about 2 minutes, turning them over. Add garlic and fry for another 3 minutes. Season with salt, pepper and lemon juice. Arrange on a plate and garnish with a slice of lemon.