Kaspar's used to be a restaurant, but now they've changed their business model. They occasionally return to being a restaurant for a few nights out of the year, but they mostly stick to catering for special events. You can use their space for your event and it is quite versatile. The have a small room in the back, full of wine bottles and it is very cozy for about 10-15 people. They also have the larger dining space if your group is bigger.
I went to a tasting where I got to try several of their featured dishes. Everything I had was fantastic. They make very hearty vegetarian dishes, which is great in the winter when you want more than a salad or pasta. They had some exotic dishes, like wild boar, which was a big hit. For dessert, they made crepes with several different fillings and toppings.
They also host several cooking classes, both private and ones you can sign up for individually. I haven't attended one myself, but I hear they are tons of fun and people actually use the recipes and tips they pick up there.