Get frietjes from a shop, and get the patatje oorlog if you're adventurous. (For shops, I liked Fabel Friet and Patat Steeg). Go to a street market and find fresh made stroopwafels and poffertjes.

Random smattering of other restaurants I liked: Winkel 43 (apple pie), Restaurant 't Zwaantje (traditional Dutch), Bacalar (fancy Mexican), Box Sociaal (Australian brunch), Sampurna (Indonesian).