1) Preheat the oven to 190 degrees C/Gas mark 5. Line standard cupcake tins with 36 liners.
2) Whisk half the oats with the flour, oat bran, bicarbonate of soda, baking powder, salt, and cinnamon in a medium bowl.
3) In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and both sugars on medium-high speed until pale and fluffy. Add the eggs, 1 at a time, beating until each is smooth, scraping down the sides of the bowl if needed. Beat in the vanilla. Turn the speed to low, add the flour mixture, and beat until combined. Beat in the sour cream. Stir in the sultanas by hand.
4) Transfer 1/4 of batter to a small bowl, and then stir the coconut and the remaining oats. Divide the plain batter among the cupcake liners, and then top each with 1 tablespoon oat-coconut batter. Bake until golden, rotating the tins halfway though, 18 to 20 minutes. Transfer the tins to wire racks to cool completely before removing the cupcakes.
For the icing:
1)In the bowl of an electric mixer fitted with the paddle attachment, beat the cream cheese, butter, and salt on medium-high speed until creamy. Turn the speed to low and beat in the icing sugar, about 75g at a time.
2) Increase the speed to medium-high and beat until light and fluffy. Add the orange zest and liqueur, beating steadily until mixed. Refrigerate the icing for 30 to 60 minutes to firm. Frost the cooled cupcakes with icing.
This recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.