Beat together the cream cheese and icing sugar until smooth.
Freeze 6 dollops of the cream cheese filling (about 2 tsp each) for 15-20 minutes.
Brush butter then sprinkle flour into the skull cavities, ensuring a good coating.
Preheat the oven to 350°F (180°C).
In a separate bowl, whisk together the dry ingredients and psyllium husk powder.
Beat the sugars and butter until creamy, then add the pumpkin and egg. Add a third of the flour mixture, followed by the maple syrup, then fold in the remaining flour.
Spoon half the batter into the bottom of each cavity in the pan, add the chilled cream cheese filling, and top with the rest of the batter. Smooth the surface.
Bake for 20–25 minutes, then let the cakes cool in the pan for 15–20 minutes before flipping them out.
To make the Icing, whisk the cream cheese and butter until smooth, then add the icing sugar. Thin the icing with milk if needed.
Remove about a teaspoon of the icing and add a few drops of red food colouring.
Lightly brush the white icing over half of the skulls, then add the red icing to the eyes.
Storage: 2–3 days at room temperature.