Position racks in upper and lower third of oven. Preheat oven to 325°F/165° Line 2 cookie sheet pans with parchment paper.

In a large bowl whisk together the melted butter and brown sugar until blended. Whisk in the vanilla, cinnamon and eggs until the mixture is smooth and well combined. Use a sturdy wooden spoon to stir in the oats, flour, baking soda and salt until blended. Stir in morsels and nuts, if using, and raisins.

Drop cookie dough by generously rounded tablespoons 2 inches (5 cm) apart on cookie sheets; flatten cookies slightly. Bake for about 10 to 12 minutes, rotating pans halfway through, or until edges and tops have just begun to turn light golden brown. The cookies will be a bit soft in the center. Place pans on racks to cool cookies completely. Store cookies at room temperature in airtight container for up to 5 days.