Preheat oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan, or line with parchment paper.

Prepare the Streusel: In a small bowl, combine the flour, granulated sugar, brown sugar, and cinnamon for the topping. Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs. Set aside.

Whisk Dry Ingredients: In a medium bowl, whisk together the 1 3/4 cups flour, baking soda, and salt. Set aside.

Cream Wet Ingredients: In a large bowl, cream together the softened butter, 1 cup granulated sugar, and 1/2 cup brown sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla extract.

Combine Batters: Gradually add the dry ingredients mixture to the wet ingredients, alternating with the milk, beginning and ending with the dry ingredients. Mix just until combined; do not overmix. Gently fold in the chopped rhubarb.

Assemble and Bake: Pour the batter into the prepared loaf pan. Sprinkle the reserved streusel topping 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 topping begins to brown too quickly, loosely tent the loaf with aluminum foil.

Cool the bread in the pan for 15 minutes, then carefully invert it onto a wire rack to cool completely before slicing.