We came to Tertin Kartano last summer when visiting Mikkeli area. Tertin Karano is a beautiful well preserved old manor house with nice garden and a small pretty lake. It has great restaurant, few rooms you can stay in and small shop where you can buy their own products like their blend of coffee and tea and marmalades, honey etc.
I warmly recommend eating in their restaurant. We had their lunch buffet which was amazing. Food was absolutely delicious. They use local ingredients and cook traditional dishes but with a twist. The restaurant is nicely decorated and you can see how much attention is put to details. So, definitely worth a visit even a bit further away as well.