1. Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners or lightly grease with non-stick spray.
2. In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt.
3. In a separate bowl, combine the melted butter, milk, eggs, and vanilla extract. Mix well until smooth.
4. Gradually add the wet ingredients to the dry ingredients, stirring until just combined. Be careful not to overmix, as this can make the muffins tough.
5. In a small bowl, mix together the cinnamon and brown sugar. Gently fold this mixture into the muffin batter, creating a marbled effect.
6. Spoon the batter into the prepared muffin tin, filling each cup about three-quarters full. If using, sprinkle chopped pecans on top.
7. Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean. The muffins should be golden brown and have a lovely aroma.
8. While the muffins are baking, prepare the glaze by whisking together the powdered sugar, milk, and vanilla extract until smooth.
9. Once the muffins have cooled slightly, drizzle the glaze over the top, letting it soak into the warm muffins. Serve immediately for the best experience.

When I first attempted this recipe, I was reminded of my abuela’s knack for sensing the perfect moment to take her creations out of the oven. The key is to trust your instincts and enjoy the process.