I suppose that this style of poor mans brioche more often than not is sweetened and stuffed with chocolate or preserved fruits. But the plain version makes a really good light loaf or can be divided as burger buns. So keep the dough whole for a loaf or divide into roughly 120g buns (940g divided by 8 = 117.5g). 120g might seem big for a bun but, if you keep them flat, they will take a lot of filling, and are light as well as being robust.
Melt the butter and mix with the milk, starter and eggs. Mix in the flour and salt. Knead ten times, rest five minutes, and repeat this process twice more.
Ferment in a plastic box (or similar) for about four hours at room temperature, stretching and folding every hour for the first three hours.
For a loaf, shape and prove in a banneton for about three and a half hours. Egg wash and bake – start at a high temperature and reduce the heat after about 15 minutes. About 40 minutes in total egg washing for a second time half way through.
For buns divide the dough by eight. Roll the pieces as you would for bread rolls but then flatten them and arrange on a baking sheet. Prove for maybe three hours, dimple then with your fingers, egg wash. Bake in a hottish oven for ten minutes then reduce the heat. About 25 minutes total.
In both cases check that they are not burning – cover with baking parchment if they are getting too dark.