quite a silly request but...
I am currently on a very restricted diet but as a reward, my doctor has given me permission to have one heavenly waffle during my upcoming trip to Belgium. So, I'd love to make it absolutely worth my while... and am asking for your suggestions as to the very best in either Brussels or Bruges - whether it be from a cart, dessert shop or restaurant!

Thanks in advance for helping with what could be the highlight of my vacation

Hi,
IMO, the absolute best waffles I've had in Brussels are from the Sunday morning market by the Ixelles ponds, near place Flagey. There's a little old guy with a stall next to the flower/plant stalls, where he makes his own gaufres de liège (Liège waffles) which are always piping hot and utterly delicious. He sells fresh coffee as well. It's a nice little market, too, and makes for a very pleasant Sunday morning stroll.

If you can't make it there, or aren't going to be in Brussels on a Sunday, you could do a lot worse than the chain called Belgaufra. They have outlets all over town, including on rue Neuve and Chaussée d'Ixelles. They make the waffles fresh from dough rather than just re-heating pre-made ones which is what a lot of the street stalls do.

A friend of mine swears by the waffle stall right next to the Mannekin Pis. I'm not such a fan of the waffles themselves (reheated usually) but they do have lots of sinful toppings like whipped cream, strawberries, chocolate, etc., which you don't always get elsewhere.

In Brussels, I liked Dandoy on rue de Beurre off Market Square. I was on a weekend jaunt and went there first thing, went upstairs and sat at a table, spread out my maps to do some planning, etc. and chowed down.
Re: street waffles, I did learn to skip the chocolate sauce, as there's no way to keep the chocolate from getting all over everything.
Jess

I'm not sure they have to be the best for you to really enjoy.

Then again, are waffles really that tasty?

We were in Brugges last year and I had read all about mussels.

We wandered around, picked an outdoor restaurant and my order was a bottomless bucket of mussels. Maybe they weren't "the best". I wouldn't know but I really enjoyed them.

My wife insists I got a "mussel" cramp.

How about eating only a large quarter each time that way you get to try all the different waffle stands. I'm no waffle connoiseur but I enjoyed every single one of them maybe because I don't live in Brussels or Brugge.

I have to second Myer's recommendation. The mussels in the Belgian restaurants are incredibly delicious, different than those on the other side of the Atlantic. The mussels come from different sources depending on the seasons, but yet they all taste great no matter what season. So save some room for the mussels, it's a must eat.