add the yeast, 1 tsp of the sugar and the warm water to a mixing bowl. Let the yeast bloom for 5-10 mins
Add half the flour, the rest of the sugar, the butter, salt, dry milk and potato flakes. Mix until mostly smooth.
Add flour 1/2 C at a time until the dough starts to thicken. Then switch to 1/4 C at a time. Make sure you give some knead time in between adding the flour.
Add flour until the dough starts to clean the sides of the bowl. Then stop adding flour and keep kneading until the dough is soft and elastic. Test it by grabbing a small ball of dough and pulling it into a square to make sure it stretches thin but doesn't rip.
Place the ball of dough into a greased bowl and cover with a tea towel. Let it rise 60-90 mins until doubled in size.
knock the dough down and divide in half. Press into a 6x8 inch rectangle and roll into a log. Place into a prepared bread pan and lest rise about 60 mins until the dough rises above the pan by about 1 inch.
preheat the oven to 350
mix the egg and water and brush onto the bread
bake the bread for 15 mins then top with an aluminum foil tent to keep from over browning and bake another 25-30 mins.
let cool slightly then slice and serve, or let cool until the next day to slice thing and use for sandwich bread.