2Make dough: Combine 1 cup flour, yeast, sugar, and salt in a large bowl. Add very warm water and oil; mix until well blended, about 1 minute. Gradually add enough remaining flour to make a soft, slightly sticky dough ball. Knead on a floured surface, adding more flour if needed, until smooth and elastic, about 4 minutes. Cover and let rest on the floured surface.
3While dough rests, make filling: Cook and stir sausage in a large skillet over medium-high heat until crumbly and browned, 5 to 7 minutes. Use a slotted spoon to remove sausage to a paper towel-lined plate to drain; discard grease from the skillet. Add spinach and water to the skillet; sauté over medium heat until spinach is wilted, 1 to 2 minutes; drain liquid. Return sausage to the skillet with spinach. Set aside.
