which counter service does not have a dessert listed? And if you're referring to the menus on here or on allears.net, remember they don't necessarily have everything on them that's actually on the real menu board at Disney.
Every counter service we've been to (both resort and in the parks) has had at least 2 choices for dessert...well, Turkey cart in MK they just have choc chip cookies as dessert. Some places you have multiple options (like big resort counter service places--it they have an ice cream area, you get to choose cones/dishes/sundaes/milkshakes...if they have bakery area, you get your choice from the bakery area. Same is true at Sunshine Seasons in The Land building/Epcot: wonderful bakery choices there.
Most counter service places in the parks, seems like it's a choice of 2 small pre-packaged cakes or yogurt parfait kind of thing.
Most places will let you take a bottled water instead of dessert.