• Preheat the oven to 400°F. Line a baking sheet with parchment paper.

For bread:

• Scrub the sweet potatoes clean, pat them dry, then pierce each several times with a fork. Place them on the lined sheet and bake until tender, about 60-80 minutes. Turn the oven off. Let the sweet potatoes cool for 20 minutes, then peel them and mash the flesh with a fork. You should have about 2-½ cups (325 grams) of roasted sweet potato pulp.
  
• In the bowl of a stand mixer fitted with the paddle attachment**, combine ½ cup warm water, the first ¼ cup (50 grams) granulated sugar, and the 3 tablespoons yeast. Let stand until mixture is foamy, about 10 minutes (less if you're using instant yeast).
  
• Add the 1 egg and the 1-⅓ cups (167 grams) flour. Beat at low speed until smooth, about 2 to 3 minutes. Remove the paddle and cover the bowl loosely with a clean kitchen towel. Let the dough rise until doubled in size, about 30 to 45 minutes. You should see small bubbles forming around the edges of mixture when it finished with the first proof.
  
• Replace the paddle attachment and add the sweet potato purée, the salt, the remaining 3 eggs, the remaining 4-½ cups (563 grams) flour, and the remaining ¼ cup (50 grams) sugar. Beat the dough at low speed until everything is incorporated, stopping to scrape sides of bowl every so often.
• Increase the mixer speed to medium and beat the dough until it is smooth and elastic, about 2 to 3 minutes. With mixer still running at medium speed, add the butter, 1 tablespoon (14 grams) at a time, letting each piece fully incorporate into the dough before adding the next piece. This will take at least 10 minutes.
  
• Grease a large bowl with cooking spray or vegetable oil. Place the dough in the oiled bowl, rotating it so the entire dough ball is greased. Cover it with a clean kitchen towel and let it rise in a warm (ideally 75°F), draft-free place until doubled in size, about 2 hours.

For streusel:

• In a medium bowl, whisk together flour, pecans, sugars, zest, and salt. Drizzle in the melted butter and stir it with a wooden spoon until combined. Crumble the streusel with your fingertips until you have medium-sized clumps.
  
• Preheat oven to 350°F. If you are making individual rolls, butter or spray two 9x13-inch baking trays with cooking spray. If you are making loaves, butter or spray two 9x5-inch loaf pans with cooking spray. Line the pans with parchment paper.
• Turn out dough onto a lightly floured surface. Punch down the dough and divide it in half. Cover the halves loosely and let them rest for 10 minutes. Working with one half at a time, roll the dough half into a 16x9-inch rectangle. Sprinkle with one-third of the prepared streusel. Starting on one short side, roll up the dough jelly-roll style and press the seam to seal.
  

Forming loaves/rolls:

• To make loaves, place the dough seam side down in the prepared 9x5-inch loaf pan. Repeat with remaining dough and another one-third of streusel. Cover and let rise in a warm, draft-free place (75°F) for 30 to 45 minutes. Brush the risen loaves with the beaten egg and sprinkle the tops with the remaining third of the streusel.
• To make individual rolls, cut the long rolled log of dough into 12 pieces by making decisive cuts with a serrated knife about 1-⅓ inches apart. Place each roll cut-side down in the prepared pan. Repeat with the remaining rolls. Cover and let rise in a warm, draft-free place (75°F) for 20 to 30 minutes. Sprinkle with the reserved one-third of streusel (no need to egg wash these).
  

To bake:

• Bake, covering loosely with foil for the first half of baking to prevent excess browning, until golden brown.This should take 30-35 minutes for rolls or 60-75 minutes for 9x5-inch loaves. A thermometer inserted in the center should register 190°F. Let the brioche cool in the pans for 10 minutes. Remove the brioche from pans and place on wire racks to cool completely.