Combine all dough ingredients except for the butter in the bowl of a stand mixer. Mix on low speed for a minute or two until the flour is all absorbed, then mix on high or medium high speed for about 10 minutes until you have a soft, smooth dough that is close to passing the windowpane test.

Add the softened butter and mix for a few more minutes until all combined. The dough should be smooth, strong, and slightly shiny. Shape it into a ball in the mixing bowl and cover. Let rise until it's nearly doubled in size, about 1 to 2 hours.

Gently deflate the dough and divide into 15-24 rolls depending on the size you want. Shape each piece into a ball. To smooth it out, cup your hands and pull the dough ball towards you to tighten the outer layer and create a smooth, round dough ball.

Place buns on a lightly greased parchment-lined baking sheet. Cover and let rise until light and puffy, about an hour to 1.5 hours.

Toward the end of the rising time, preheat the oven to 375°F.

Make an egg wash by mixing one egg with a splash of milk or cream. Mix until you have one cohesive liquid, then brush over the buns before baking. Sprinkle with coarse sea salt if desired.

Bake for about 16-18 minutes for small buns, or about 25 minutes for large buns (around 100g), until golden or the middle of a roll reads 190F on a thermometer.

Optional: once they're out of the oven, brush with melted butter or rub a cold stick of butter over the top of the rolls.