Being a "veggie" has long ceased to mean you need feel you're an outsider in the Spanish capital. Over the past decade and a half, the traditional dominance of carnivore-oriented establishments has been challenged by an ever-growing number of vegetarian restaurants. In this guide, you find nine of the best.
You don't have to confine yourself to 100% green establishments to get the goods, though, as many standard Spanish eating spots offer a large choice of noncarnivorous platos.
Apart from the ubiquitous tortilla (made, naturalmente, with eggs Spanish-style and not from cornmeal Mexican-style), check out their menus for dishes like pimientos fritos (fried peppers), berengenas al horno (eggplant baked in the oven), calabaza guisada (stewed pumpkin), setas al jerez (mushrooms cooked in sherry), and pisto (Spain's answer to ratatouille with tomatoes, peppers, eggplant courgettes, and onions all cooked in oil and garlic: avoid the Manchego version, though, as this has bits of ham in it). Jamón (Mountain or cooked, Serrano or York) is scarcely regarded as "real" meat in Spain and can even appear in apparently innocuous dishes such as caldo (broth), so confirm with the waiter before you order.
Arabic, Indian, and Italian restaurants may also provide what you're looking for, with their inventive range of couscous, rice, and pasta-based dishes, and if fish is an acceptable option there are, of course, plenty of seafood restaurants to choose from, though these tend to be expensive. (Check the restaurant list for top-value spots like Ribeiro do Miño.)
Potato power: Anyone wanting a racion, or single dish, of something cheap and meat-free should try patatas bravas (potatoes sautéed brown and served in a picante sauce). Between Sol and Tirso de Molina, there's a trio of eating spots all called Las Bravas and all specializing in this simple but filling dish (still a modest 3.50€ dish). It's also widely available in tapas bars, sometimes at even cheaper prices.