Preheat and Prepare: First, preheat your oven to 180°C (160°C fan) and line a 12-hole muffin tin with paper cases.

Combine Dry Ingredients: In a large bowl, whisk together the plain flour, bicarbonate of soda, baking powder, cinnamon, ginger, nutmeg, and salt. This ensures the spices and leavening agents are evenly distributed.

Mix the Wet Ingredients: In a separate, medium-sized bowl, whisk together the light brown sugar, eggs, vegetable oil, pumpkin purée, and vanilla extract until everything is smooth and well combined.

Make the Muffin Batter: Pour the wet pumpkin mixture into the dry flour mixture. Gently fold them together with a spatula until just combined. Be careful not to over-mix; a few small lumps of flour are perfectly fine.

Prepare the Cream Cheese Filling: In another bowl, use an electric hand mixer (or a stand mixer) to beat the softened cream cheese and caster sugar on medium speed until smooth and creamy, about 1-2 minutes. Add the egg yolk and vanilla extract and beat again until just incorporated.

Assemble the Muffins: Fill each muffin case about two-thirds full with the pumpkin batter. Then, place a generous dollop (about 1 tablespoon) of the cream cheese filling on top of the batter in each case.

Create the Swirl: Take a toothpick or the end of a small knife and gently swirl the cream cheese filling into the pumpkin batter. I find that just two or three circular motions are enough to create a lovely marbled pattern without fully mixing the two together.

Bake to Perfection: Place the muffin tin in the preheated oven and bake for 20-22 minutes. You'll know they're ready when a skewer inserted into the pumpkin muffin part comes out clean (testing the cream cheese part will be wet). The tops should be golden and springy to the touch.

Cool Completely: Let the muffins cool in the tin for about 5 minutes before carefully transferring them to a wire rack to cool completely. They are lovely warm, but the cream cheese filling sets up better as they cool.