Preheat your oven to 175℃ (350°F). Gather your ingredients and prepare your loaf tin.

Brush your loaf tin with butter or oil, and dust it with flour or line it with parchment paper.

In a large mixing bowl, cream the softened butter until light and fluffy, about 2 minutes, then gradually add soft brown sugar.

Add eggs one at a time to the creamed mixture, beating well after each addition.

In a separate bowl, whisk together self-raising flour, baking powder, salt, and pumpkin spice mix until evenly combined.

Gently sift one third of the dry flour mixture into the creamed mixture, fold it in, then add half of the milk, continuing to fold gently.

Fold in the vanilla extract until thoroughly mixed into the batter.

Scoop one third of the batter into a separate bowl, sift in the black cocoa powder, and mix well.

In the remaining batter, sift in pumpkin powder and add orange food coloring, stirring until combined.

Transfer the batter into the prepared loaf tin, alternating layers of orange and black batter, and swirl with a skewer.

Bake in the preheated oven for about 45 minutes, check for doneness with a skewer, and let it rest in the tin for a few minutes.

Sift powdered sugar and mix in warm water to achieve a smooth glaze consistency.

Drizzle the glaze over the cooled cake and add sprinkles and eyeball candy for decoration.