Put flour, salt, yeast, sugar, and butter into a mixer bowl. Use your fingers to mix butter into the flour until it is completely combined.
Add water and mix well. If you have a stand mixer, use the dough hook to mix the dough for 5 minutes. The dough shouldn't be too sticky, but there shouldn't be any flour left on the bottom or sides of bowl.
Remove the dough from bowl and knead until it is stretchy. This means you can pull on it and won't immediately break apart.
Let rise for at least an hour, or until doubled.
Line baking sheet with parchment paper. Tip dough onto counter and form into a ball, then flatten to about 2" thick.
Let rise an hour or until doubled.
Preheat oven to 425° F. Cover the top with flour. Make vertical slashes from center to bottom. Bake 30 minutes, or until an instant-read thermometer registers 190°F. when inserted in the middle.
Cool on wire rack.