Here are some breakfast options:

Le Pain Quotidien (Parvis St-Pierre)16 Parvis Saint Pierre
1180 Bru
02/344 04 14
Site: www.lepainquotidien.com  

Tables d’hôtes’ with great charm and fine products, bread is made in the traditional way.

Mokafé

Galerie du Roi 9 Koningsgalerij
1000 Bru
02 511 78 70

Open from 7 a.m., Sunday 8 a.m. This place Is located in the famous St. Hubertus Gallery, a nice glass covered gallery, close to the famous Grand Place. In the same gallery, another nice place to have a coffee or breakfast is the Vaudeville Café, the first floor is really worth a visit, and their cakes are delicious, and important is that you always get an homemade sweet ( like chocolate mousse) with your coffee, because in Belgium you never get your coffee without a sweet treat.