Celioso is an amazing bakery with lovely cupcakes and sandwiches as well as good coffee: great atmosphere and excellent customer service - Cl Hortaleza 3, 28004 Madrid. Check their website here
I tried their chcocolate and peanut butter cupcake and thought it was divine!
I also tried the vegetarian and vegan restaurant Yerbasbuenas - Cl Borbadores n3. I had vegetarian paella and also loved their falafels. Check their site here.