note - if you are using frozen rhubarb for this re thaw the rhubarb the night before in a sieve, over a bowl, and discard the excess liquid.3 cups all-purpose flour1 1/2 cups packed brown sugar1 tsp. baking soda1 tsp. salt2 eggs1 cup buttermilk or 1 cup milk including 1 tbsp. vinegar or lemon juice2/3 cup