Butter Mochi Muffins

Name: Butter Mochi Muffins
Cuisine: American, Asian, Japanese
Ingredients: 1/4 cup 2 ounces unsalted butter, melted and cooled, plus more for greasing pans (sub brown-butter ); 2 cups 320 grams mochiko sweet rice flour (Koda Farms); 1 cup 200 grams organic dark brown sugar* (regular light or dark brown sugar will work); 2 teaspoons baking powder; 1/2 teaspoon kosher salt (1/4 tsp sea salt); 1 13- ounce can full-fat coconut milk (Sub evaporated milk, half to all); 2 large eggs (room temperature); 1½ teaspoons vanilla extract; 1 teaspoon molasses (optional, added for flavor or use Golden Syrup or honey); 1½ tablespoons each (black and toasted sesame seeds, for garnish)