Step 1

Let 1 stick unsalted butter sit at room temperature until softened. Meanwhile, place 1/2 cup maple syrup in a medium saucepan over medium heat and bring to a simmer. Reduce the heat to medium-low and simmer until reduced by a quarter, 10 to 12 minutes (keep a close eye, as the syrup could boil over!). The syrup will look thick and coat the back of a spoon and the bubbles in the pan will be larger and slower. Remove from the heat and let cool completely, 20 to 25 minutes.

Step 2

Beat the butter in a large bowl with an electric hand mixer until smooth and creamy, about 1 minute. (Alternatively, beat the butter with a whisk.) Add the cooled maple syrup, 1/2 teaspoon kosher salt, and 1/2 teaspoon ground cinnamon. Beat until fluffy and lighter in color, 1 to 2 minutes.