One of the very first places I ever ate at in Amsterdam was Cafe De Jaren. And thankfully it’s still a place I’m come back to over and over again these past 11 years. It’s your basic cafe setting. The food is fine (I’m particular to their tomato soup) but what I often come back for is the deck at the back side which opens onto the Amstel River. If you get there at about mid-day when the weather’s nice you’ll have a great view of the river and all the boats passing by. It’s easy to sit for several hours just taking in some beers and borrelhapjes (dutch snack foods such as bitterballen, kroketen, ossenworst, kaas, etc…).
Upstairs is typically reserved for people wanting to have a proper meal; downstairs more a cafe setting, and outside on the patio you can of course order what you want. I do believe most everything is available at every section of the cafe.
It’s very centrally located not too far from either the Rembrandt square or the flower market.