As far as I can tell, the light sauce is made with cream cheese, the 'lettuce' is really coconut flakes, and the 'ketchup' sauce is strawberry paste.
The only component that doesn't have a substitute ingredient is the cheese slice that's between the 'lettuce' and 'ketchup'. The 'bun' itself tastes like chocolate, and is sprinkled with sesame seeds on both sides.
The resulting taste? A one-of-a-kind blend of both sweet and savoury flavours sandwiched between a crispy and chewy macaron.