If you’re walking around Casa da Música, I would strongly recommend grabbing something to eat at the Porto Rico Confeitaria. This is one of those traditional and family run pastry shops with more than 50 years of experience, where for sure you’ll find the best snacks whether salty or sweet, most of them produced by them, right there.
I must warn you that it is preferable to go there on take-away mode since it isn’t a big place and staff is always in a hurry, but that’s ok, ’cause the snacks are absolutely worth it. My favorites are undoubtedly the ‘digestivos’ (on the picture), an addictive, slightly warm, delicious salty snack of which I’m only able to eat 2 or 3 pieces, believe me, I usually bring home around 500gr, which lasts a maximum of 2 days. Every time I go there I have to ask either for a croquette or panado (breaded pork – very typical) to eat as I wait, since the smell of this shop makes me want to eat right away, so avoid going there starving, or you’ll bring most of the shop home with you.
I remember coming here when I was little with my mother and it is amazing that the taste of the majority of the snacks just hasn’t changed at all. This is a typical place for the true Portuenses (people who are born in Porto) to go to, but it goes quite unnoticed if you haven’t been told about.