Fiestas de San Isidro (rosquillas tradition) ★ 4.5
Fiestas de San Isidro on May 15 is Madrid's patron saint festival, with the city's bakeries selling rosquillas tontas y listas (sweet ring biscuits) and the Pradera picnic of empanadas and tortillas.
Tip: Free entry; rosquillas at Horno de San Onofre and La Mallorquina (10 to 14 euros per box). Pradera picnic on May 15.