Bring a large saucepan of water to a boil. Add 2 tsp salt and the sliced sweet potatoes. Let cook for 4 minutes until they start to soften but are not mushy. Rinse with cold water, drain and set aside.

Combine flour and 2 tsp salt in a large bowl. Whisk to thoroughly combine. Dissolve yeast in the warm water then add to the bowl along with 3 Tbsp olive oil. Stir together until combined then knead briefly until smooth. Cover bowl and let rise for 40 minutes. Transfer bowl to the refrigerator and let rest for 2 hours. This will allow the dough to fully hydrate. NOTE: We strongly recommend you weigh your einkorn flour, if possible, for better accuracy. If you don’t have a scale, fluff the flour with a fork before you measure it in a cup.

Pour dough onto a lightly floured surface and give it a couple good kneads to smooth it out. This dough will look pretty rough when you take it out of the refrigerator, but will come back together after kneading.

Using a rolling pin, roll out dough to approximately 18" x 14". If the dough seems stiff and hard to roll, let it rest and warm up a bit, then continue.

Sprinkle 2 tsp of rosemary on half of the dough closest to you running lengthwise. Fold the uncovered half of the dough over the covered half. It will now be very long and skinny (approx. 9" x 14"). Sprinkle 2 more tsp rosemary on the right half of the dough, then fold the left half over the right half. Now it should be about 9" x 7".

Using the rolling pin, roll the rosemary into the dough, making the dough about 12" x 17" or so. Pour 3 Tbsp olive oil into a baking sheet and transfer the dough to the pan. Use your fingertips to dimple the dough.

Arrange sweet potato slices then sprinkle with Gruyere cheese and a few whole rosemary leaves over the top. Cut onion slices in half and sprinkle over top then drizzle a generous amount of olive oil over everything. Cover well and let rest for 40 minutes.

While the dough rests, preheat oven to 475 degrees.

After the dough has rested, place the baking sheet in the oven. Shut the oven door and immediately turn the oven down to 375 degrees.

Bake for 15–17 minutes until the internal temperature is 200 degrees.