A Leonardo da Vinci Mystery by Diane A. S. Stuckart
I don’t know if a historical mystery can also be classified as a “cozy” but it fits with this book. The book cover calls it a “Leonardo da Vinci Mystery”. Leonardo is not really the crime solver, however. It is Dino, his apprentice, that takes front stage.
The jacket review quotes call the book “mesmerizing” and a “tour de force”. I would not go that far. I would call the book entertaining. Not only is the story itself good, but the glimpse into 15th century Italy and the world of this great artist and inventor is very enjoyable.