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Center a rack in the oven and preheat oven to 325. Butter a 9 x 13 baking pan and put on a baking sheet.
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Whisk together the flour, baking powder, baking soda, and salt.
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Working with a stand mixer, preferably fitted with a paddle attachment, or with a hand mixer in a large bowl, beat the butter on medium speed until smooth and creamy. Add both sugars and beat for another 3 minutes, or until well incorporated. Add the eggs 1 by 1, beating for 1 minutes after each addition, then beat in vanilla. Reduce the mixer speed to low and add the dry ingredients, mixing just until they disappear into the batter. Using a rubber spatula, stir in the chips, nuts, and coconut. Scrape the batter into the buttered pan and use the spatula to even the top as best as you can.
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Bake for 40 minutes, or until a knife inserted into the center of the blondies come out clean. The blondies should pull away from the sides of the pan a little and the top should be a nice honey brown. Transfer the pan to a rack to cool for about 15 minutes before turning the blondies out onto another rack. Invert onto a rack and cool the blondies to room temperature right side up.
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Cut into 32 bars, each roughly 2 ¼ x 2 ½ inches.