Bloom the Yeast
Combine warm water and yeast with a pinch of the sugar in a small bowl. Let sit for 5-10 minutes until foamy.
Mix the Dough By Hand
In a large bowl, whisk together flour, remaining sugar, and salt. Add the yeast mixture and softened butter. Mix until a shaggy dough forms, then turn out onto a lightly floured surface and knead for 8-10 minutes until smooth and slightly tacky (not sticky).
Stand Mixer
Add flour, remaining sugar, salt, and butter to the mixer bowl fitted with the dough hook. Pour in the bloomed yeast mixture. Mix on low (speed 1-2) until it comes together, about 1-2 minutes. Increase to medium-low (speed 2-3) and knead for 6-8 minutes until the dough pulls cleanly from the sides of the bowl and looks smooth. If it climbs the hook, it's too dry - add a splash of water. If it won't come together, add flour a tablespoon at a time.
The dough is ready when you can do the windowpane test: pinch off a small piece and stretch it thin. If you can see light through it without it tearing, gluten is developed.
First Rise
Lightly oil the dough ball and bowl. Cover and let rise in a warm place for about 1 hour, or until doubled in size.
Shape
Press down on the dough with your palm a few times to release the large gas bubbles. Fold the edges toward the center, flip seam-side down, then shape into one large loaf or two smaller loaves. Place on a parchment-lined baking sheet.
Second Rise
Cover loosely with a towel or plastic wrap. Let rise another 30-45 minutes until puffy.
Score and Prep
Using a sharp knife or lame, score the top with 3 diagonal slashes about 1/4 inch deep. Brush with water or milk for a softer crust (egg wash for a shinier finish).
Bake
Preheat oven to 375°F. Bake for 25-30 minutes until golden brown and the loaf sounds hollow when tapped on the bottom.