01 -
Set your oven to 375°F/190°C to preheat. Prepare muffin tins by either greasing well or lining them with paper cups.
02 -
In a medium bowl, stir together the flour and baking powder. Add a pinch of salt here only if you're using unsalted butter.
03 -
Whisk the sugar, eggs, and buttery goodness in a big bowl. Mix in the vanilla, milk, and rum until it lightens in color.
04 -
Slowly fold the dry mix into the wet one. Stir in the butterscotch chips when nothing powdery is left. The mixture will look quite thick.
05 -
Scoop 4 tablespoons of batter into each muffin tin hole. Add extra chips or sugar on top, if you want. Bake for 20-24 minutes, and test with a toothpick—it should come out mostly clean.
06 -
Give the muffins about 5-10 minutes to rest in the pan. After that, transfer them to a rack to cool off completely—or enjoy them warm!