In a large bowl stir yeast into 1 cup lukewarm water until dissolved. Let sit until small bubbles form around edges. Whisk in sugar, salt and egg until thoroughly blended. Using a wooden spoon, stir in flour and butter until dough comes together. Mix gently with your hands until it forms a smooth ball of dough. Return dough to cleaned bowl and cover with plastic wrap. Let rise until doubled, about 1 1/2 hours. Turn out dough onto work surface and gently squeeze out air bubbles. Fill and shape as desired.
Yield: dough for 1 loaf