Step 1

In a small bowl, dissolve yeast and sugar in warm water. Meanwhile, finely chop enough rhubarb to measure 1/2 cup. Slice each remaining rhubarb rib lengthwise into 4 thin strips; cut strips into 4-in. pieces; reserve for topping.

Step 2

In a large bowl, combine 2 cups flour, 2 tablespoons oil, 1 teaspoon salt, chopped rhubarb and the yeast mixture. Remove and finely chop rosemary leaves from 2 sprigs (discard stems); add to flour mixture. Beat on medium speed until smooth. Stir in enough remaining flour to form a soft dough (dough will be sticky).

Step 3

Turn dough onto a floured surface; knead until smooth and elastic, 6-8 minutes. Place in a greased bowl, turning once to grease the top. Cover and let rise in a warm place until doubled, about 25 minutes.

Step 4

Preheat oven to 450°. Punch down dough. Turn onto a lightly floured surface; divide into 4 portions. Roll each portion to a 7x5-in. rectangle. Place on a parchment-lined baking sheet. In a small bowl, whisk egg with remaining 2 tablespoons oil; roll reserved rhubarb strips in egg wash. Gently press 3-5 strips into top of each piece of dough. Brush remaining egg wash over tops. Remove leaves from remaining rosemary sprig; sprinkle leaves over tops (discard stem). Sprinkle with remaining 1/2 teaspoon salt and the pepper.

Step 5

Bake until golden brown and rhubarb is tender, 13-15 minutes. If desired, drizzle with honey before serving.