Prepare the oven and pans: Preheat your oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or lightly grease with butter or non-stick spray. This ensures your muffins lift out cleanly and have those perfect golden edges.

Mix the dry ingredients: In a large bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and cinnamon. Stir well to make sure the leavening agents are evenly distributed — this helps the muffins rise evenly as they bake.

Combine the wet ingredients: In a separate bowl, whisk together the buttermilk, melted butter, egg, and vanilla extract until smooth. The buttermilk adds a subtle tang that balances the tart cranberries beautifully.

Make the batter: Pour the wet ingredients into the dry mixture and gently fold them together using a spatula. Be careful not to overmix — it’s okay if the batter looks slightly lumpy. Overmixing can make the muffins dense instead of fluffy.

Add the cranberries and pecans: Fold in the cranberries and chopped pecans until evenly dispersed. If you’re using frozen cranberries, keep them frozen so they don’t bleed too much color into the batter.

Fill and bake: Scoop the batter evenly into the prepared muffin cups, filling each about 3/4 full. Bake for 18–22 minutes, or until the tops are golden and a toothpick inserted into the center comes out clean. Let them cool in the pan for 5 minutes before transferring to a wire rack.

Prepare the glaze: In a small bowl, whisk together the powdered sugar, milk, and vanilla until smooth and slightly runny. Adjust the consistency by adding more sugar to thicken or a few drops of milk to thin.

Glaze the muffins: Once the muffins are completely cool, drizzle the glaze generously over the tops using a spoon or piping bag. Let it set for a few minutes until it forms a light sugary crust.