Cook paste - Add the flour and water to a small saucepan and use a whisk to combine. Place over medium heat and whisk continuously for about 2-3 minutes until the mixture thickens to a smooth, pudding-like consistency.

Cool down - Transfer the mixture to a small bowl and press plastic wrap directly onto the surface. Let it cool down to room temperature before using. This can be made a few hours before using. Do not place in the fridge.

Mix dry ingredients - Add the plain flour, sugar, salt, yeast and milk powder to the bowl of a stand mixer. Use the dough hook attachment to mix until combined.

Mix wet ingredients - In a large jug whisk together the eggs and milk until well combined.

First knead (15 min) - Add the wet ingredients and cooled tang zhong to the dry ingredients. Use the dough hook to mix the ingredients. Turn the mixer on 30% (that’s speed two on my Kenwood) and knead for 15 minutes.

Rest dough - Turn the mixer off and cover the bowl with plastic wrap. Rest the dough for 10-15 minutes.

Second Knead - Knead the dough for 5 minutes on speed 2 (30% speed).

Add the butter and finish kneading - With the mixer on speed 2, add the softened butter a little at a time, letting each piece mostly mix in before adding the next. This will take about 5 minutes all up. Once all the butter is added, knead on medium low speed for about 5-10 minutes until the dough is smooth, elastic and comes away cleanly from the bowl.

Room temp rise (Proof #1) - Add the dough to a large sized mixing bowl and cover with plastic wrap. Let it rise in a warm spot of the house for 1 hour or until doubled in size.

Cold rise (Proof #2) - Place the bowl of dough in the fridge for at least 2 hours, or up to 8 hours (overnight) for better flavor.

Divide and shape - Turn the chilled dough onto a lightly floured surface and divide into 10 pieces, aprox 58g each. Working quickly, roll each piece into a ball.

Final proof (Proof #3) - Arrange the buns on two large baking trays lined with baking paper. Cover loosely with greased plastic wrap and rise in a warm spot for about 1-3 hours.

Bake - Preheat your oven to 195C / 385F (fan off), 175C / 350F (fan on). Gently brush buns with egg wash. Bake for 12 minutes until golden, light to lift, and fully cooked through. Cool completely before filling.

Prepare mascarpone cheese - Add the mascarpone to a large mixing bowl and use a spatula to stir and break up.

Whip remaining ingredients - Add the cold heavy cream, powdered sugar and vanilla to the mascarpone. Whip to stiff peaks.

Use a serrated knife to slice every bun in half from the top but not all the way to the bottom so it can hinge open. Then pipe in about 1 ½ tsp of jam at the bottom of the open bun. Pipe some cream over the top of the jam to seal it.

Use a spoon to create a divot at the top of the bun and fill with a small round dollop of more jam.