In a small pan, mix together all the ingredients for the tangzhong. Heat on medium heat until mixture thickens and looks like thick pudding. Remove from heat and pour into a container to cool in the fridge.
In the bowl of the standmixer, add bread flour, sugar, yeast, and salt. Mix together.
Attach dough hook, add the warmed soy milk, oil, and the cooled tangzhong mixture. Put speed on medium speed and mix until a dough forms (about 15 minutes). Scrape down sides halfway through. When done, it should be smooth, with slight dimpling.
Roll into a ball and place in a lightly greased bowl. Cover with a damp cloth and place in a warm place to proof for 1 hour to 90 minutes or until double in size.
Punch down dough. Cut into four equal pieces. Roll each into a ball and let rest under a damp towel for 15 minutes.
Put a ball on a lightly floured surface, roll out to a rectangle about 8"x4". Fold each small end to the middle, also called a 3 fold. Flatten and rotate 90°. Repeat the folding and rolling. Finally, roll into a log.
Butter a 8 1/2" x 4 1/2" loaf pan and place the logs seam-side down Repeat with each piece of dough. Cover with a damp cloth and proof for 45 minutes.
Preheat over to 350℉
Mix syrup wash and brush the top of the proofed doughs. Bake for 30-35 minutes. If browning too quickly, add foil to the top.
Remove from oven and immediately brush with butter.
When wrapped well, you can store at rm temp for 5-7 days or in fridge for 10 days. Or in freezer for up to 3 months.