Preheat the oven to 350°F (175°C) and line a 12-cup muffin pan with paper liners or lightly grease it.
Prepare the streusel topping by combining the flour, brown sugar, and cinnamon in a small bowl. Add the butter and use your fingers or a fork to mix until the mixture resembles coarse crumbs. Set aside.
In a large mixing bowl, combine the flour, baking powder, baking soda, and salt. Whisk until everything is evenly distributed.
Using an electric mixer, beat the eggs with the sugar in a separate large mixing bowl on medium speed until the mixture is light and slightly frothy. Add the vanilla extract, yogurt, and vegetable oil, then continue mixing until the batter is smooth and creamy.
Using a rubber spatula, gently fold the chopped rhubarb into the batter, stirring until well incorporated.
Next, add the flour, baking powder, baking soda, and salt mixture to the wet ingredients, stirring gently until combined.
Divide the batter evenly among the 12 muffin cups using a spoon.
Add the streusel topping by sprinkling the crumb mixture generously over each muffin, pressing down lightly so it adheres to the batter.
Bake for 25 minutes, or until the tops are golden and a toothpick inserted into the center of a muffin comes out clean.
Let the muffins cool in the pan for about 10 minutes, then remove them from the muffin tin and transfer them to a wire rack to cool completely. Enjoy!