Prep: Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone mats and set aside. Lightly grease spaces on the baking sheet with a brush of neutral oil or softened butter if desired.

Dry ingredients: In a medium bowl whisk together the all-purpose flour, baking powder, baking soda, and 1/2 teaspoon kosher salt until evenly combined. Set aside.

Cream butter and sugars: In a large bowl or the bowl of a stand mixer fitted with the paddle attachment, beat 1 cup (226 g) unsalted butter, the light brown sugar, and granulated sugar together on medium speed until the mixture is light, aerated and has lost some of the gritty sugar texture, about 2 to 3 minutes. Scrape down the bowl as needed.

Add egg and extracts: Add the large egg, 2 tablespoons pure maple syrup, and 1 teaspoon vanilla extract to the butter-sugar mixture and beat on low until just combined. Do not overmix.

Combine wet and dry: With the mixer on low, add half the dry ingredients and mix until incorporated, then add the remaining dry ingredients and mix just until a soft dough forms. The dough should be slightly sticky but able to hold a shape when scooped.

Scoop cookies: Using a 2-tablespoon cookie scoop or spoon, portion dough into evenly sized balls and place them about 2 inches apart on the prepared baking sheets. Gently press each ball to flatten slightly so they will bake into a round, single-layer cookie. You should get roughly 20 to 24 cookies depending on exact scoop size.

Bake: Bake one sheet at a time in the center of the preheated oven for 10 to 12 minutes, or until the edges are set and the centers look just baked but still soft. The tops will be pale golden. Rotate the pan halfway through baking if your oven runs unevenly.

Cool for icing: Remove the cookies to a wire rack and allow them to cool completely before icing. While they cool, prepare the brown butter icing.

Brown the butter: In a small saucepan over medium heat, melt 6 tablespoons (85 g) unsalted butter. Continue to cook, swirling the pan occasionally, until the butter foams and then the milk solids turn deep golden brown and emit a nutty aroma, about 4 to 6 minutes. Immediately transfer the browned butter to a small heatproof bowl to stop cooking and allow it to cool for 3 to 5 minutes so it’s warm but not scalding.

Make icing base: In a medium mixing bowl, whisk together 2 1/2 cups (300 g) powdered sugar, 1 tablespoon pure maple syrup, and a pinch of kosher salt. Slowly add 1 tablespoon of the warm browned butter and whisk to combine; add the remaining browned butter as needed. If the mixture is very thick, whisk in 1 to 2 tablespoons heavy cream or whole milk until you reach a thick, spreadable consistency. The icing should be glossy and hold its shape when spread.

Adjust and test: Taste the icing and add more salt if it needs contrast or an additional splash of maple syrup for more maple depth. If the icing becomes too thin, add a few tablespoons more powdered sugar; if it’s too thick to spread smoothly, add a drop more cream.

Ice the cookies: Using an offset spatula or the back of a spoon, spread a thin, even layer of the brown butter icing over each cooled cookie. Aim for a smooth, glossy finish; the icing will firm as it cools.

Set and store: Allow the icing to set at room temperature for at least 30 minutes. Store the finished cookies in an airtight container at room temperature for up to 3 days or refrigerate for up to a week. Bring refrigerated cookies back to room temperature before serving for best texture.