Super Soft Japanese Milk bread- Tangzhong Bread

2 Loaves Tangzhong roux (30g flour + 150 g water) 570 g bread flour(High Protein Flour: 12.7% protein) 60 g sugar 10 g dry instant yeast 10 g salt 260 g milk 1 egg 50g butter 50g Tangzhong Pan size: One open pan- 12cm x 23cm x7 cm height One top cover pan - 12cm x 22 cm x 11cm height