- Make Dough: In a large mixing bowl, whisk together 2 cups flour, 1 teaspoon salt, 1 Tablespoon white sugar, and yeast. Add water and stir until no dry spots remain. The dough will be very stick, but just scrape down the sides and you stir. 
- First Rise (30 minutes): Cover the dough with a clean dish towel and leave it on the counter to rise until puffy, 30 minutes.  
- While dough is rising, brush a loaf pan with cooking oil or spray with nonstick cooking spray. Place the loaf pan on a sheet pan (this will just catch any cinnamon crunch pieces that fall off during baking).  
- Make Cinnamon Streusel: In a small mixing bowl, whisk together brown sugar, 1/4 cup white sugar, cinnamon, and 1/4 teaspoon salt. Add melted butter and stir until evenly combined. Add 1 1/4 cups flour and mix with a fork until the mixture is even (it will be thick and dry).  
- Assemble Bread: After dough has been rising for 30 minutes, use your hands to scatter about 3/4 of the cinnamon streusel mixture over top, breaking it apart with your hands as you go. Gently fold the cinnamon mixture into the dough until it is evenly combined.  
- Tip the dough into the prepared loaf pan, using a spatula if needed to help ease it out. Brush the surface of the loaf with whisked egg and then crumble the remaining cinnamon streusel over top. 
- Preheat oven to 375°F / 190°C. 
- Second Rise (30 minutes): Place the bread near the oven and leave to rise until it nears the top of the loaf pan, about 30 minutes. 
- Bake bread until the top is golden brown and crisp, 40 to 45 minutes. (The bread is done with it reaches 190°F / 88°C in the center.) 
- Allow the bread to cool for 10 minutes in the loaf pan. Gently turn it out onto a rack to cool completely. (Make sure to allow it to completely cool before slicing it - if it's still warm it may compress and that can give the center a gummy texture.) 
- Slice and serve.