The Jam Hotel is quiet new in the neighborhood but it became quickly a "place to be". Close to public transport, the seventh floor of the hotel is a beautiful rooftop with one of my favourite view on Brussels (especially for sunsets). There's also a small pool and amazing cocktails!
This place is not well known by tourist (yet..). The vibe is good and you can go whenever you want (coffee in the morning, ice tea in the afternoon or cocktail in the evening). It's a chill place where you can just relax and even dip a foot in the pool while drinking an aperol ;)
The restaurant on the ground floor is amazing!