01 -
Preheat oven to 350°F (175°C). Grease a 9×9-inch baking pan with baking spray, line it with parchment paper, and set aside.
02 -
Whisk together flour, baking soda, cinnamon, and salt in a medium bowl. Set aside.
03 -
In a large mixing bowl, beat butter and brown sugar using a mixer until light and fluffy, about 2–3 minutes. Scrape down the sides as needed.
04 -
Beat in eggs one at a time until fully incorporated. Stir in vanilla extract.
05 -
Gradually add the dry mixture to the wet ingredients, mixing until just combined. Fold in oats and raisins with a spatula. The dough will be thick and sticky.
06 -
Spread the dough evenly in the baking pan, optionally sprinkling extra raisins on top. Bake for 18–20 minutes, or until the edges turn golden.
07 -
Cool the bars in the pan for 5–10 minutes, then transfer to a wire rack using the parchment paper. Allow to cool completely before frosting.
08 -
In a mixing bowl, beat butter until smooth. Gradually add powdered sugar, then maple syrup, heavy cream, cinnamon, and optional maple extract. Beat until frosting is creamy and spreadable.
09 -
Spread the frosting evenly over cooled bars. Slice into squares and serve.