Combine flour through baking soda in a large bowl. Cut butter into mixture with pastry knife. Add extract and slowly add buttermilk, mixing until dough is formed.
In a large ovenproof skillet, add rhubarb, strawberries, sugar and ¼ cup water.
Cover and cook over medium heat for 15 minutes, stir occasionally. Combine remaining ¼ cup water and cornstarch. Pour into rhubarb mix; bring to a boil and cook for 30 seconds. Turn heat to low and drop dough by 2 tablespoons full into rhubarb sauce.
Cover and cook about 20 minutes until dumplings are baked through. If desired, brown under broiler for 2 – 3 minutes. Top with heavy cream or dollop of Greek vanilla yogurt.