Please note that I have included two methods below for tangzhong making and dough kneading using either conventional or Thermomix method so do take note of the sub-headings.

[CONVENTIONAL] Tangzhong & Dough Kneading

• Prepare tangzhong by mixing flour in water and whisk together in a pot, ensuring the mixture is well combined with no lumps. Cook over medium-low heat, stirring consistently to prevent burning and sticking while you cook.
• The mixture will gradually become thicker. Once you notice that some “lines” appear in the mixture for when you stir with the spoon, it’s done. Your tangzhong is ready.
  
• Transfer into a clean bowl. Cover with a cling wrap sticking onto the surface of tangzhong to prevent it from drying up. Let cool.
• If using bread machine, add all ingredients into breadmaker except butter; first the wet ingredients (tangzhong, egg, milk, cream), then followed by the dry ingredients (milk powder, sugar, salt, flour, yeast). Select "dough" mode and let knead until all ingredients come together, usually I let it knead for approximately 10-12 minutes. Then add in the butter, continue kneading until the dough is smooth and elastic. My bread machine's dough kneading cycle is 23 minutes.

  If using stand mixer, add all dry ingredients (flour, sugar, salt, milk powder, yeast) into mixing bowl and whisk to combine. Then add wet ingredients except butter (tangzhong, egg, milk, cream). Knead using dough hook on low speed for 12-15 minutes until well incorporated. Then add butter and continue kneading for another 8-10 minutes until dough is smooth and elastic, and passes the window pane test.
• Transfer dough to pastry mat or a greased bowl, shape into ball by tucking the sides of the dough downwards whilst rotating in one direction until smooth and taut. Let rise, covered loosely with cling wrap/damp towel until doubled in size (approx. 45-60 minutes).

[THERMOMIX] Tangzhong & Dough Kneading

• To make tangzhong, place 20g high protein flour and 100g water/milk in mixing bowl, cook for 1min/75°C/spd 2 and let stand for 10-15 minutes until temperature lowers down to 37°C.
• Once temperature hits 37°C, add milk, whipping cream, sugar, egg and yeast, then mix 30 sec/spd 2.
• Add remaining 270g high protein flour, milk powder, salt and butter then mix 30secs/spd 6. Proceed to knead 4 min.
• Transfer dough to pastry mat or greased bowl, shape into ball then let rise, covered loosely with cling wrap/damp towel until doubled in size (approx. 45-60 minutes). 

Dough Shaping

• After dough has doubled in size, punch or press down to deflate. Divide dough into 10 equal portions and roll into a round shape. Let rest, covered for 10-15 minutes - this bench rest will ensure dough is easier to handle.
• To shape buns, roll out each portion into an oval shape then fold ⅓ from each sides to the center. Rotate so that dough is now horizontal then roll and lengthen it slightly.
• Rotate again to place dough vertically, use the corner of your palms to press the sides together on the bottom end to form a V-shape.
  
• Use a sharp knife/pastry cutter to slice through the middle up to ¾ long from the top, leaving the bottom ¼ attached.
  
• The dough will now resemble a Y-shape. Fold both ends of the top inwards towards the center, forming a ♡ shape. Transfer to a lined baking sheet. Place each dough 2 inches away from one another.
  
• Let dough rise for its 2nd round of proofing, until double in size. This takes another 35-40 minutes depending on the weather.
• During last 15 minutes, preheat oven to 180°C and prepare tuna topping. Finely dice a small to medium red onion, then mix with drained tuna. I like using spicy tuna. If using tuna in oil/spring water, you would want to add about 2 tbsp mayo and season with some salt and pepper. If you like you may even add some corn kernels.
• Egg wash the buns, then top with one tablespoon of tuna mixture in the center, ensure it is spread evenly. Pipe kewpie mayo in zig-zag motion, then garnish with some dried parsley flake.
• Bake at 180°C for 15-20 mins. Remove from oven, and let cool for 5 minutes then transfer onto a wire rack to let cool completely. Store in air tight container.