
These muffins are perfect for breakfast, after-school snacks, or tucked into a lunchbox, with a soft, moist crumb and just the right touch of sweetness.
Make the muffins:
Preheat the oven to 350 F. Line a 12-cup muffin pan with paper liners and set aside.
In a large bowl or stand mixer, beat the softened butter and brown sugar together on low speed until well-combined.
Add the oil, then beat in the eggs one at a time, mixing on low speed after each addition.
Mix in the pumpkin purée, vanilla, cinnamon and salt until just combined.
Add the flour, baking powder and baking soda. Stir gently by hand until the flour is mostly incorporated.
Add the buttermilk (or Greek yogurt) and fold in until just combined. Do not overmix.
Scoop the batter into the prepared muffin pan, filling each liner about 3/4 full (a 1/4-cup measuring cup works well for portioning).
Bake for 20 to 25 minutes, then check for doneness. Continue baking for an additional 5 to 10 minutes, until a toothpick inserted in the center comes out clean.
Remove from the oven and let cool completely before icing.
Make the cinnamon icing:
Whisk together powdered sugar, milk, cinnamon and vanilla until smooth.
Drizzle over the cooled muffins before serving.