In the mixer bowl stir together yeast, ½ cup flour/oats and the warm water (~95°F, 35°C).
Cling wrap mixer bowl and ferment 30 minutes
Add salt and brown sugar to remaining flour mixture and mix.
Add beer, butter and remaining flour mixture into the mixer bowl. I go back in forth with some beer then some flour mixture. As long as the beer is room temperature I do not find it necessary to warm it. If the dough keeps sticking to the side of the mixer bowl, add a small amount of flour.
Knead 8 minutes.
Cling wrap and ferment 2 hours .
Punch down, form in pan or boule.
Proof 30 minutes.
Place a pizza stone on oven bottom shelf.
Set oven to 375°F/190°C/Gas 5.
Preheat for 15-30 minutes.
Optional:Finishing the CrustWash dough with egg mixed with 1 TBSP water. Sprinkle sesame seeds or oat flakes on top OR Cornstarch glaze with seeds or flakes OR Wash dough with olive oil.
Place in oven.
Bake 40-45 minutes.
Cool on wire rack.
Recipe by On Bread Alone at https://onbreadalone.com/recipes/stout-beer-oat-bread/