Preheat oven to 400°F. Line a 12-cup muffin tin with paper liners or grease well with butter.
In a large bowl, whisk together 1 1/3 cups all-purpose flour, 1 cup yellow cornmeal, 1/3 cup light brown sugar, 1 tbsp baking powder, 1/2 tsp kosher salt, and 1/2 tsp ground cinnamon until evenly combined. Make a well in the center.
1 1/3 cups all-purpose flour, 1 cup yellow cornmeal, 1/3 cup light brown sugar, 1 tbsp baking powder, 1/2 tsp kosher salt, 1/2 tsp ground cinnamon
In a separate bowl, whisk together 1 cup buttermik, 1/2 cup pure maple syrup, 1/2 cup canola oil, 2 large eggs, and 1 tsp vanilla extract until completely smooth.
1 cup buttermik, 1/2 cup pure maple syrup, 1/2 cup canola oil, 2 large eggs, 1 tsp vanilla extract
Pour the wet ingredients into the well in the dry ingredients. Using a rubber spatula, fold gently just until the flour disappears. Let the batter rest for 10 minutes at room temperature so the cornmeal can fully hydrate.
Divide the batter evenly among the 12 muffin cups, filling each about three-quarters full. Bake on the center rack for 18–20 minutes, until the tops are deeply golden, springy to the touch, and a toothpick inserted in the center comes out clean.
While the muffins bake, beat 1/2 cup unsalted butter until light and fluffy, about 2 minutes. Add 3 tbsp pure maple syrup, 1 tsp ground cinnamon, and 1/2 tsp sea salt. Beat until fully incorporated and creamy.
1/2 cup unsalted butter, 3 tbsp pure maple syrup, 1 tsp ground cinnamon, 1/2 tsp sea salt
After removing from the oven, let the muffins cool in the pan for 5 minutes, then transfer to a wire rack. Serve warm with a generous swipe of the maple cinnamon butter.