1. Wash the chicken cutlet. In Senegal, we usually wash it with salt and lemon to remove its strong smell.
2. Prepare the seasoning by combining the garlic, bell pepper, chili peppers, salt and ½ a teaspoon of pepper.
3. Chop the cutlet into four.
4. In a bowl, place half of the seasoning, add one tablespoon of mustard, the juice of a lemon and one tablespoon of oil. Combine then add the chicken pieces to the bowl. Leave to stand for one hour.
5. During this time, thinly slice the onions. Add one tablespoon of mustard and mix together.
6. Pour one tablespoon of oil into a frying pan and add the onions. Leave to cook, stirring occasionally. When the onions become transparent, add the rest of the seasoning and lightly salt and pepper. Add the red chili pepper. Add a little water (around 5 cl) then leave to simmer on a low heat. Mid-way through cooking, add the juice of half a lemon. The sauce is ready when there is no water left.
7. Grill the chicken on the barbecue. Drain the marinade from the chicken, add a tablespoon of oil, then use the mixture to coat the chicken pieces as they cook.
8. Spread the (pre-cooked) rice over a baking sheet, cover with another sheet, then press hard to bind the grains of rice.
9. Using a cookie cutter, make eight rice patties. To make the sandwiches, take a rice patty and drizzle a spoonful of Yassa sauce over it. Stack a piece of chicken cutlet, two slices of cucumber and a slice of tomato onto the patty before placing another rice patty on top and garnishing with slice of lemon.
A tip from Aïssatou: squeeze the slice of lemon over your ""Yassandwich"" before eating.