Melt 5 tablespoons butter in a saucepan over low heat; remove from burner and set aside.
Melt remaining 2 tablespoons butter in a very large skillet over medium heat; add pears and cook, turning occasionally, until mostly tender, about 6 minutes. Sprinkle sugar over pears and cook until browned and tender, about 3 minutes. Cover skillet and keep warm over low heat.
Combine whole wheat flour, all-purpose flour, cinnamon, baking soda, ginger, and salt in a large bowl; make a well in the center. Mix melted butter, eggs, molasses, buttermilk, and milk in a separate bowl. Pour butter mixture into the well of the flour mixture and stir just until batter is moistened and slightly lumpy.
Preheat and grease a waffle iron according to manufacturer's instructions.
Pour batter into preheated waffle iron and cook according to manufacturer's instructions; repeat with remaining batter. Serve each waffle with pears and 1 tablespoon vanilla yogurt.