Do you throw out the rinds from Parmesan cheese? Stop! Save them in a Ziploc bag in the freezer for the next time you make Bolognese sauce and drop 2 or 3 in as soon as the sauce begins to simmer. People will wonder what the secret is to your delicious Bolognese. Our motto here at Rock Recipes is &quot;No flavor left behind!&quot; Find this tip in our recipe for an outstanding simple slow-cooked Bolognese sauce.