Here's what I would do for that shirt:
you would need 1 beige tank top, some lighter beige pieces of felt for the sesame seeds (although I don't believe mcdonald's burgers actually have them), one long, thick strip of dark brown, yellow, red, and green fabric (a little longer than the others for the green), and a sewing machine.
Sew or glue the felt pieces on the top part of the shirt. Then, sort of like a ruffled skirt, but not so ruffly and on a shirt, start with the dark brown fabric and sew the top side of the fabric to the shirt, leaving the bottom hanging. Then do the same with the other layers, but with the lettuce, fold it over sort of like pleats every once in a while so it's fluffy and ruffly like real lettuce. that way it won't be too too unstretchy and she can spin around and it will look cool
I would suggest sewing the layers like this
so you don't have to worry about using different colored threads because nobody will be able to see them. It will also give the layers some dimension.
Hope that helps!