1. Stir the yeast and warm water together in a small bowl, and let stand until foamy, about five minutes.

2/ Place 1 1/2 cups of the flour in the work bowl of a stand mixer. Make a well in the flour, and add the yeast mixture. Stir the egg, 1 tablespoon of the oil, and 1 1/2 teaspoons of the salt together in the small bowl with a fork, and add that to the well, also. Using the fork, mix the liquids with the flour until a soft dough forms, and almost all the flour has been incorporated.

3. Fit the mixer with the dough hook and knead on medium-high speed until smooth and elastic, about 4 minutes, adding some or all of the remaining 1/4 cup flour, as necessary, to prevent the dough from sticking to the bottom of the bowl. Transfer the dough to a bowl coated with the olive oil spray, and turn to coat. Cover with plastic wrap and let rise in a draft-free corner for 1 1/2 to 2 hours, until doubled in bulk.

4. While dough rises, heat 1/3 cup of the oil in a large skillet over medium-high heat. When hot, add the fennel seeds, and cook, shaking pan, for about 30 seconds, until just beginning to darken. Add the onions, one teaspoon of the salt, season with pepper, and stir with tongs to lift the fennel seeds into the onion mixture. Reduce heat to medium-low and cover onions directly with a round of parchment paper cut to fit the pan. Cook, stirring occasionally, until onions are very tender and golden brown, 1 1/4 to 1 1/2 hours.

5. Heat a separate skillet over medium-high heat. When hot, add a tablespoon of the olive oil, then the kale, and season with the remaining 1/4 teaspoon salt, plus pepper. Cook, stirring frequently, until kale has wilted, about 6 to 8 minutes. Set aside.

6. Preheat the oven to 375F, and arrange a rack in the center of the oven.

7. Punch the dough down, and use a floured rolling pin to roll the dough out on a lightly-floured surface to the size of a large (12” by 15”) baking sheet. Transfer the dough to the sheet, and crimp the edges, if desired. Brush edges with the remaining tablespoon of olive oil.

8. Using a small offset spatula or plastic scraper, spread the mustard out over the dough. Spread the caramelized onions evenly over the mustard, then the kale over the onions, then the cheese over the kale.