Put the beef fat in the fryer and heat it to 150 °C.
Peel the potatoes, cut them into slices, and then cut them into sticks. Place the fries in cold water.
Remove the fries from the water and pat them dry.
Fry the fries for the first time in the beef fat and let them drain and cool.
Wash the lettuce, spin it dry, and place it in a bowl.
Make the bound vinaigrette.Put the mustard in a bowl.
Add the egg yolks, lemon juice, pepper, and salt and whisk. Gradually add corn oil while whisking very slowly. Whisk until you have a thick, bound vinaigrette.
Grind the meat finely with a meat grinder.
Peel the onion and chop it finely. Chop the parsley finely. Cut the pickles finely.
Mix the meat with the bound vinaigrette. Add the Worcestershire sauce, mustard, egg yolks, capers, pickles, parsley, and onion and mix. Season well with pepper and salt. Adjust the taste with tabasco.
Increase the temperature of the fryer to 180 °C.
Fry the fries a second time until they are crispy. Let them drain on kitchen paper.
Serve the tartare with the fries, possibly with some fresh mayonnaise and lettuce.
Tips
Do you still want fresh mayonnaise? Then proceed with the bound vinaigrette, but add more oil and keep beating until you have a thick mayonnaise.