Chris M.
Yelp
Whenever I'm in Prague, I make it a point to go here. At least once.
Housed above the beautiful Cubist Museum in the famed 'House of the Black Madonna', this landmark cafe has a very interesting history that is fortunately printed on their menu in full. In short, it was designed by the architect from the ground up (even the light fixtures) and while sitting in it's classic wooden booths or on it's private balcony, you can almost imagine it as it once was.
Nostalgia aside, this cafe is absolutely beautiful and a fine example of Cubism. There are almost always seats free, thanks to it being a bit hard to find for the average tourist, but if you want one of the luxurious benches or private-only-for-2-tables outside, you might need to wait.
The food is very good, although recommended for breakfast or lighter eaters. A wide selection of pancakes (from sweet to meat) are available, as well as assorted sandwiches and breakfast spreads. The Turkish Coffee is absolutely delicious.
No matter what you order, and if you at all ever enjoyed sweets, make sure you order the Chocolat Fondant, which must be Czech for 'most delicious thing ever'. A slice of the richest chocolate heaven covered in Marzipan with a side of whipped cream and stewed plums. It's worth it to come in for a coffee and this alone.