Thanks a lot for your help! Petals, the "ice cream cake" is a brilliant idea and eminently doable in a tiny place like mine. Deep-fried ice cream less so, because I only have one deep fryer which is exclusively reserved for hand-cut chips (sorry, fries).
My restaurant serves quality country-style fare, including new or different interpretations of local German dishes. Since we are in a touristy area, with late spring to early autumn being the main season, we have to try to cater for two distinct customer groups, namely "enlightened" city tourists and conservative villagers. The latter do like my food, but require relatively large servings and largely ignore starters (let alone desserts). For example, there's a local sports group with a pre-ordered menu booked in for Sunday evening. Nobody has ordered starters or dessert!
The city people are more open to interesting stuff around the mains and do order starters, but by the time they're finished with their main, few of them will want a dessert.
It seems to be a bit of a catch-22 situation.
Koukouvagia: I normally serve things like pancakes/crepes with roasted nuts and local honey, Greek yoghurt with fruit compote, lemon posset, panna cotta etc. Those who do get to taste it love it and sometimes come back for more. It's definitely not too sweet (in the way many Mediterranean desserts might be), I get wife and staff to taste things, too.