In this case waffles are always a good idea. And I have a soft spot for Gaufres de liège and so I changed my recipe to fit in sweet starter instead of yeast. But be aware that kneading egg and butter under the starter can be a little bit messy. If you want to keep clean hands, a mixer is maybe a better solution.
The waffles taste as good as the original ones, maybe even better due to the preferment. The only problem I face now is that I have to find a new waffle maker. The plastic of my cheap one started to break into pieces. So if you have any suggestions for a good waffle maker?