If you always look for the “home cooking” sign when you’re on the road, Casa Marta is your kind of place. Although the menu is longer than it would be in most Madrid households, the plain recipes are the sort that home cooks have made since the place was founded in the 1920s as Casa Eladio. We’ve always held that you can judge a casual restaurant by its croquetas, and these are excellent: lots of flaky tuna, a slight crunch of onion, and a béchamel thick enough to hold its shape and thin enough to explode in your mouth. Other homey plates include calf’s liver smothered in onions and roasted peppers stuffed with ground meat.