For the streusel topping:
For the crust:
For the filling:
Preheat oven to 350°F.
Prepare the streusel topping by combining the brown sugar, flour, and almonds in a medium bowl. Using two knives, cut in butter until coarsely mixed. Set the streusel topping aside.
To make the crust, blend the flour and sugar in a food processor. Add butter and pulse until mixture resembles coarse meal. Grease an eight-inch square baking dish, then line with foil and grease the foil. Press mixture into dish. Bake until crust is golden brown around the edges, about 15 minutes.
To make the filling, melt the two tablespoons of butter in a large nonstick skillet over medium heat. Add pear slices, lemon juice, brown sugar, ginger, and cinnamon. Cook, stirring occasionally, until the pears are coated and softened. Spoon pear mixture over slightly cooled crust and spread evenly to the edges. Crumble streusel topping over pears. Bake until golden and bubbly, about 18 minutes. Allow to cool before slicing into bars. These can be made a day in advance and refrigerated.