A local, Helena Fátima, who posts on the travel boards, Fodor´s, Rick Steves and TA, says that the best Francesinha would be found at Santiago, Lado B or Brasão. I keep Helena’s excellent Porto suggestions in my Porto file.
Your friend is very lucky to be staying at such a lovely, beautifully decorated and historic hotel, the Infante Sagres, Porto’s original “Grande Dame”! It was taken over by Hospes from Taylor Fladgate last year, and I see that they have kept the stylish Vogue Café.
I ate a Lado B a couple of weeks ago when I was in Porto. I have nothing to compare it to, but I really appreciated the option that I could order a half Francesinha. It was indeed delicious, and a plenty big portion for me.
I ordered a small French Onion soup and a small chocolate mousse last time I was Geneva, and I appreciated the option. European restaurants offer a lot of options I wish were available more frequently in the States and in Canada.