Preheat oven to 350 degrees. Butter an 8-inch by 8-inch baking dish.

Melt butter in a sauté pan over medium high heat. Add diced pears and sauté until they begin to brown slightly around the edges, 3 to 5 minutes. Add sugar and cinnamon and continue to cook until golden brown and lightly translucent, about 3 more minutes. Remove from heat and cool.

Combine all-purpose and whole wheat flour, brown sugar, butter, and salt in the bowl of an electric mixer fitted with the paddle attachment. Beat on low speed until the mixture resembles coarse meal with butter pieces no larger than pea-sized. Measure out ⅔ cup and set aside.

Whisk pumpkin, sour cream or Greek yogurt, sugar, cinnamon, nutmeg, cloves, allspice, ginger, and baking soda together. Add to remaining dry mixture in mixing bowl and beat until smooth. Add eggs one at a time, mixing well to incorporate.

Pour batter into pan and evenly distribute caramelized pears over the top in a single layer. Cover pears with reserved dry mixture.

Bake until golden brown and pulling away slightly from the edges of the pan, about 75 minutes or until a tester inserted in the center comes out clean. Cool on a rack 20 minutes before running a knife around the inside edges of the pan to loosen.