The patroness of Cossato is Santa Maria Assunta, celebrated on 15 August. The parish church dedicated to her was raised before the year 1000, and rebuilt in 1614 after it collapsed two years earlier.
Since 2014 the feast has had its own sweet as well: the «biscotti dell'Assunta», whose recipe was created in the workshop of the Pasticceria Pezzaro of Cossato specifically for the patronal feast, and which are sold at the parish church throughout the festivities.
