Isn't "Belag" to translate by "garniture" and "Quark" by "caillebotte"?
This "Größe M" means "Size M" and not only "oeufs (grands)" => maybe "gabarit M" ?? because XL is "grand" ;-)...
definitely not "garniture", as you could see on the link I posted above, it is ONE possible translation, not retained because of the ingredients that are more employed for a covering than for what you put inside. If it is a pastry, maybe would you add (in another part of the recipe, not visible here) some extra ingredients to give taste to the recipe (I say that because one spoonfull of sugar for 500g of white cheese is very few, so it must be something else (not told here) added for the taste of it (my humble opinion)