How to Make It
To prepare the sponge, dissolve yeast and honey in warm water in a large bowl, and let stand 5 minutes. Lightly spoon all-purpose flour into dry measuring cups; level with a knife. Stir all-purpose flour into yeast mixture. Cover and chill overnight.
To prepare dough, stir yeast mixture with a spoon; let stand 30 minutes or until it begins to bubble. Combine yeast mixture, bread flour, whole wheat flour, 1 tablespoon oil, and 2 teaspoons sea salt in a large bowl. Beat with a mixer at medium speed for 15 minutes or until dough pulls away from sides of bowl. Cover and let rise in a warm place (85°), free from drafts, 1 hour or until doubled in size (dough will be wet).
Spread 1 teaspoon oil evenly over bottom of a 15 x 10-inch jelly roll pan. Pour dough into pan; let stand 5 minutes. Gently press dough to fill pan; let stand 30 minutes.
Preheat oven to 425°.
While the dough is rising, prepare topping by heating 1 teaspoon oil in a large nonstick skillet over medium heat. Add onion and rosemary, and cook 15 minutes or until browned. Arrange onion over top of the dough. Sprinkle with 1/4 teaspoon sea salt and crushed red pepper. Bake at 425° for 25 minutes or until golden brown. Cool 5 minutes.