This recipe is from one of our most beloved books: King Arthur Flour's Whole Grain Baking (Countryman Press, 2006; p. 69-70) - adapted from the Peach Coffeecake recipe.
"This is a very quick cake to put together. The scent of baking cinnamon from the crunchy top provides its own allure, and the peaches baked into the whole wheat batter give it a wonderfully comforting moistness. When baked with rhubarb (see variation. below) the stalks tend to melt into the batter, where the rhubarb lends its distinctly citrusy tang and moisture, without drawing too much attention to itself. In either form, this coffeecake is sure to become a favorite."