Are there any native speakers here? When I started Duolingo they called sandwiches "emparedados," now they just say sandwiches with a spanish accent (as did a Mexican friend of mine). But I had learned from my Spanish family that sandwiches were called bocadillos. In spanish class in high school I was taught to say tortas for sandwiches, but in Spain torta means cake (tarta is also used). I've never heard pasteles used as cake from anyone, and from get togethers with the Puerto Rican side of my family I can safely say that I would not want pasteles for dessert... or ever. It would be cool to see how others say both "sandwiches" and "cake" along with the dialect you speak, or region you learned spanish from.
I do believe it would be understood. Whether or not it is the correct wording I couldn't say. You may want to use "Cuantas rebanandas de pastel" or maybe "Cuantas porcions de pastel", as both would directly translate to "How many slices of cake". However, I'm sure saying something like "How much cake" is acceptable.
…But it was not asking, “How many pieces of cake,….” but, “How many cakes….”
“We are having an office party and need a variety of cakes.”
“What did you have in mind?”
“Maybe some chocolate, some yellow cake, maybe some angel food cake, and carrot cakes.”
“Okay. How many cakes do you want?”
I feel like Duo should teach you more words, the only sweets you learn are cakes and chocolates and that weird girl with the sugar on the apple. Then each level you just use the same words in different sentences. Each level should EXPAND your knowledge and SOLIDFY the existing information in my opinion. Does anyone else feel that way?