In a bowl, soak the raisins in 1 cup of warm water or orange juice for 10-15 minutes. Drain, then blot dry with a paper towel.
1 1/4 cup raisins, 1 cup orange juice
Meanwhile, in another medium mixing bowl, whisk together the oats, all purpose flour, baking soda, salt, and cinnamon.
2 cups old fashioned rolled oats, 1 3/4 cups all purpose flour, 1 teaspoon baking soda, 1 teaspoon salt, 1 teaspoon cinnamon
In the bowl of an electric mixer, beat together the butter and sugar on medium speed until creamy and a bit lighter in color, 2-3 minutes. Beat in the eggs, one at a time, then stir in the vanilla.
1 cup (2 sticks) unsalted butter, 1 1/2 cups packed brown sugar, 2 eggs, 2 teaspoons vanilla extract
Add the flour mixture to the bowl and beat on low speed until combined. Drain the raisins very well, then add all but 1/4 cup of them to the bowl along with the nuts, if using. Beat on low speed until well distributed.
1 3/4 cups all purpose flour, ½ cup chopped walnuts or pecans
Cover the dough with saran wrap, then place in fridge to chill for at least 2 hours or overnight.
Preheat the oven to 350 degrees and line two sheet pans with silicone mats or parchment paper. Scoop 2 Tablespoon portions of dough onto the prepared sheet pans, then bake for 11-14 minutes, rotating the pans and shuffling top to bottom midway through. Remove the cookies from the oven when the outside is browned but the inside still looks light in color, puffed, and soft.
If desired, use a large upside down glass or round cookie cutter to shape the cookies. Place the cutter on top of the cookies and spin it around a few times for a perfect round shape. Dot the cookies with the extra 1/4 cup of raisins. Allow to set up on the pan for 10 minutes, then transfer to a wire rack to cool completely.