The sweet potato needs to be measured precisely, so either go by weight or ensure you have exactly 1 1/4 cups of small-cubed potato.
Steam the diced sweet potato in a steamer or steamer basket for 30 minutes, or until fall-apart tender. (Do not steam in the microwave, because it will dry out the sweet potato out rather than infusing it with moisture.) Add the steamed sweet potato to a food processor and process for 1 minute, or until puréed, stopping to scrape down the sides as needed.
In a small bowl, gently whisk together the warm water, pure maple syrup, and yeast. Let stand for 5 minutes, or until a foam develops on the surface.
Meanwhile, lightly grease a large glass mixing bowl with coconut oil.
Add the yeast mixture, plus the spelt flour, 1 tablespoon of the coconut oil, 1 teaspoon of the cinnamon, vanilla, and the sea salt to the sweet potato puréee in the food processor. Pulse five 5 times, and then process for 15 seconds, or until the dough begins to wrap itself around the blade of the food processor. The dough should be very soft, very sticky, and shaggy yet pulled together around the blade. If it's too loose or too wet, add more spelt flour, 1/4 cup at a time, and pulse until the desired texture is reached. Alternatively, if it’ is too dry or dense, add more warm water, 2 tablespoons at a time, and pulse until the desired texture is reached.
Pull the dough from the food processor (yes, it should and will stick to your fingers) and turn out onto a clean work surface that has been generously dusted with spelt flour. Knead for 1 1/2 to 2–2 1/2 minutes (set a timer if you can), or until the dough is smooth and springy, adding more spelt flour as needed (I usually add about another 1/4 cup, but if you added more than 3 1/2 cups while blending in the food processor, you may not need to add more flour now). You’ll know the dough is ready when it begins to hold its shape and springs back, slightly but not completely, when pressed. The gluten in spelt is delicate, so be careful not to over-knead or you’ll end up with dry, crumbly bread.
Shape the dough into a ball and place it in the prepared bowl. Cover the bowl with a clean kitchen towel, and let the dough rise in a warm place for 1 hour, or tripled in size. (Simple test for readiness: poke a finger tip about 1 inch into the dough. If the dough retains the indentation, it's good to go.)
When the dough has just a few minutes left to rise, lightly grease a 5" x 10" loaf pan with coconut oil. Whisk together the coconut sugar and remaining 1 tablespoon of cinnamon in a small bowl.
Punch down the dough and turn it out onto a clean, generously floured work surface. Roll the dough into a 1/2-inch- thick rectangle (approximately 9 inches by × 15 inches).
Lightly brush the top of the dough with the remaining 1 tablespoon of melted coconut oil. Then, sprinkle with the coconut sugar and cinnamon mixture.
Starting at the short edge of the rectangle, gently roll the dough away from you until you have a tightly wound roll. Use your fingers to pinch the seam closed.
Carefully transfer the loaf to the greased loaf pan, swirled-side-down. Loosely cover the pan with parchment paper and let the loaf rise in a warm place for another 30 minutes, or until doubled in size.
Meanwhile, preheat the oven to 350˚F.
Bake on the middle rack of the oven for 18 to 24 minutes, or until just barely turning golden on top. The top should feel firm to the touch and the loaf should sound hollow when gently tapped. (Note: this baking time yields a loaf with a thin crust, soft and fluffy interior, and doughy, gooey center. Think Cinnabon. If you prefer a non-gooey center, bake for 24 to 28 minutes, or until desired doneness is reached.)
Remove from the oven and transfer the pan to an oven-safe cooling rack. Allow the loaf to cool in the pan almost completely before serving.
I recommend slicing off pieces just before enjoying rather than slicing the entire loaf. This keeps the bread from going stale. Serve on its own or slathered with virgin coconut oil or vegan butter.
Store the loaf in the pan at room temperature, loosely covered with foil, for up to 3 days. Alternatively, refrigerate for up to 1 week.