Use a sharp knife to cut out the stalk of lettuce. Put the whole lettuce upside down under a cold running tap, allow the water to get between the layers, and separate the leaves. Slice cheese.
Combine all patty ingredients (except oil) in a bowl. Divide and shape mixture into one patty per person about 2 cm thick.
Heat oil in a frypan on medium heat. Cook patties (in batches if needed) for 4-5 minutes each side, until golden brown and cooked through. Place cheese on top and cover with a lid. Cook for a further 1 min until cheese melted.
Fill lettuce cups with patties, salsa, mayo and jalapeños. Wrap up and enjoy!