Preheat your oven to 350°F (175°C). Grease and flour a standard 9x5 inch loaf pan, or line it with parchment paper, leaving an overhang for easy removal.

In a large bowl, whisk together the flour, baking soda, and salt. Set aside. In a separate medium bowl, whisk together the 1 cup of granulated sugar, eggs, oil, milk, and vanilla extract until well combined.

Gently fold the wet ingredients into the dry ingredients until just combined. Do not overmix; a few streaks of flour are acceptable. Gently fold in the chopped rhubarb pieces.

Prepare the optional streusel topping: In a small bowl, combine the 1/2 cup flour, brown sugar, and nutmeg. Cut in the cold butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs. If skipping the streusel, combine the remaining 1/2 cup sugar and 1 tablespoon cinnamon for a simpler topping.

Pour the batter evenly into the prepared loaf pan. Sprinkle the streusel topping (or cinnamon-sugar mixture) evenly over the top of the batter.

Bake for 50 to 60 minutes, or until a wooden skewer inserted into the center comes out clean or with moist crumbs attached. If the top begins to brown too quickly, loosely tent the loaf with aluminum foil.

Let the bread cool in the pan for 10-15 minutes before carefully lifting it out onto a wire rack to cool completely before slicing.