Adapted from google images
cup butter, softened
tsp baking soda
cups rhubarb, chopped (3 medium stalks)
cup brown sugar, packed
1.) Preheat oven to 350 degree F. In a large bowl of a standing mixer, beat butter and sugar until light and fluffy, about 3 minutes. Beat in egg. In a separate bowl, whisk together flour, baking soda and salt. With the mixer speed on low, beat in 1/3 of the flour mixture, followed by 1/2 of the buttermilk, and repeat (ending with the flour mixture). 2.) Toss rhubarb with 1 tbsp of flour. fold into cake batter. Spread into buttered 13 x 9" baking dish. In a small bowl, combine remaining 1/4 cup butter with cinnamon and brown sugar. Sprinkle over top of cake. Bake for 45 minutes to 1 hour, until centre is set and springs back when lightly touched. Serve warm or at room temperature.