Preheat the oven to 425℉ and either grease or line a 12-cup muffin tin with paper liners.
In a large mixing bowl, whisk together the flour, salt, baking soda, and spices until well combined, then set aside.
In another bowl, whisk together the melted butter, neutral oil, vanilla extract, molasses, and light brown sugar until smooth. Add in the egg and sour cream, whisking again until fully combined.
Add the wet mixture to the dry ingredients, gently folding them together until just combined; be careful not to overmix.
Divide the batter evenly among the muffin tin openings, filling each one to the top. If desired, sprinkle coarse sugar on top before baking.
After 5 minutes at 425℉, reduce the oven temperature to 350℉ while keeping the muffins inside. Continue baking for an additional 14-15 minutes or until a toothpick comes out clean.