Place the butter in a medium saucepan or skillet. Cook over medium heat until the butter melts and begins to foam.
Continue cooking, stirring occasionally, until brown specks begin to form at the bottom of the pan and the butter has a nutty aroma. Remove the pan from the heat and allow to cool to room temperature. If desired, strain the butter to remove some or all of the browned bits.
Whisk together the flour, cinnamon, baking powder, and salt. Stir in the oats. Set aside.
Using an electric mixer on medium speed, beat the cooled butter, sugar, brown sugar, eggs, and vanilla until thoroughly combined. Gradually add the flour mixture, mixing just until combined. Stir in the dates and nuts. Refrigerate the dough for 20 to 30 minutes, or until it is firm enough for scooping.
Preheat oven to 350 degrees F. Line baking sheets with parchment paper or silicone liners.
Drop dough by tablespoonfuls onto the prepared pans. Bake 12 to 16 minutes, or until the edges are browned and the centers appear set.
Cool the cookies on the pan for 5 minutes. Then transfer them to a wire rack to cool completely.
Combine the confectioners’ sugar and maple syrup in a small bowl. Add 2 teaspoons of milk, and combine until smooth. Add additional milk if needed to attain the desired consistency.
Drizzle the glaze over the cooled cookies. Allow the glaze to set for about 20 minutes before serving. Yields 48 cookies. Recipe by Jennifer McHenry - Bake or Break.