Preheat oven to 350 F. Lightly spray an 8 x 8 inch pan with nonstick spray and line the pan with parchment paper, leaving some excess paper on two sides to make the bars easier to remove from the pan once baked.
Melt or brown the butter. To brown the butter, melt the butter in a saucepan over medium-low heat. Stir occasionally at first. Once begins to bubble and comes to a boil, stir it constantly. It will start to foam. Continue stirring as you watch for it to turn a light, amber color and develop a nutty smell which should happen in about five minutes. Pour the brown butter into a heat safe bowl, making sure the scrape the bottom of the pan for all the bits. Set the butter aside to cool slightly. In the meantime, continue with the recipe.
In a large bowl, whisk to combine the flour, spices, baking soda, granulated sugar, brown sugar and salt. Use a spatula to stir in the butter, egg and vanilla. Gently fold in the raisins and oats.
Press the mixture evenly into the prepared pan. Bake 22-24 minutes, until the top is golden brown. Cool completely in the pan before cutting.
Notes
Oats: Use rolled oats. I don't recommend using quick-cooking oats.Chai spice: Instead of the spices in the recipe, feel free to swap in 2 or 2 and 1/2 teaspoons of your favorite homemade or store bought blend of chai spice. Brown sugar: Make sure your brown sugar is fresh and free of hard lumps. Storage: Store leftover bars in an airtight container at room temperature for up to 5 days or in the refrigerator fot up to 1 week. Enjoy cold or warmed slightly. Freeze for up to 1 month. Thaw overnight in the fridge.