Preheat the oven to 400 degrees. Grease an 8-cup muffin tin.
In a large bowl, whisk together the flour and baking soda. Stir in the finely chopped rhubarb. In a medium bowl, mix together the maple syrup, yogurt, egg, melted butter and vanilla. Stir into the flour mixture, just to combine. Do not over mix.
Spoon into prepared muffin tin and bake until a toothpick comes out clean, about 12 – 15 minutes. Let cool in pan for 3 minutes before removing.