Pre-heat oven to 220C (430F). Add cupcake liners into a cupcake tin.

Mix all the dry ingredients in a large bowl: flour, baking powder, baking soda, spices, salt and chopped white chocolate. If you wish to add more white chocolate to the top, reserve some (or add more!).

Brown the butter: Cube butter into smaller pieces so it melts evenly. Melt on medium low until it smells nutty. It will become bubbly, but just keep going. Use a light colored pan to see the browning. Stir occasionally. It takes somewhere between 5 to 10 minutes. Let it cool slightly but not set.

Mix all the wet ingredients in another bowl: the cooled brown butter, brown sugar, eggs, pumpkin puree, milk and vanilla extract.

Using a spatula, fold the wet ingredients into the bowl with the dry ingredients. Do not overmix, just until it's smooth and free of flour lumps.

Make the crumb topping: cube butter and add all the ingredients to a small bowl. Using two forks, mash everything together until the butter is in pea sized pieces or smaller.

Fill the cupcake tins with batter up to the brim. This makes a nice dome to the muffins. Sprinkle with more white chocolate and the spiced crumb topping.

Bake first on 220C (430F) for 5 minutes, then reduce to 190C (375F) for 12 minutes.

Drizzle with a mix of cream cheese and powdered sugar, if desired.