De Waaghals (= The Dare-devil) is a very nice vegetarian restaurant. The atmosphere is informal, but the food is very nice, refined and creative. Organic ingredients are used as much as possible. Each month a dish focuses on a different country.
The Bartolotti is perhaps one of the most beautiful Museum Houses Amsterdam has, built by someone who once was the richest man in the city, but it's a bit hidden in plain sight. These days, it is run by a group of lovely old ladies, who can't wait to offer you tea or juice. You can walk around the house like you live there.
You have to ring the doorbell to get in.
(picture from Google, by Arjan Bronkhorst)