1. Using an immersion blender, purée the thawed spinach with the hot water. Combine the flour, salt, baking powder, spinach purée and oil in the bowl of a standing mixer. Mix on slow speed until it forms a cohesive and smooth dough.
2. Cover dough with plastic wrap and let rest 15 minutes. Divide the dough into 16 balls and roll each into a 4-inch circle.
3. Heat a large ungreased heavy skillet over medium-low heat and cook the tortillas, 2-3 at a time, for 2 minutes, or until done, turning halfway.
Per serving: 354 calories, 14g fat, 1g saturated fat, 0mg cholesterol, 330mg sodium, 49g carbohydrate, 2g fiber, 1g sugar, 7g protein