First, assemble the crumb topping. In a medium size bowl, stir together the rolled oats, brown sugar, flour, and cinnamon. Cut in the butter with a pastry cutter or two knives until the mixture is crumbly and resembles bread crumbs. Set the crumb topping aside.

Preheat your oven to 375 F.

Grease a 8x8" or 9x9" square or round cake pan and lightly sprinkle with flour. (In the photos I've used two smaller round cake pans.)

In a large bowl, beat together the butter and brown sugar until light and fluffy. Then beat in the egg and vanilla.

In a medium size bowl, stir together the flour and baking powder, cinnamon, and nutmeg.

Measure out the milk.

To the large bowl of wet ingredients, add ⅓ of the dry ingredients, and mix until just moistened. Then add ½ of the milk and mix until incorporated. Again, add ⅓ of the dry, ½ the milk, and the last ⅓ of the dry, mixing between each step. The batter will be very thick.

Gently fold in the pear.

Pour the batter into the prepared pan, smoothing it flat. Sprinkle the crumb topping evenly over the cake.

Bake cake for 40-45 minutes, until a toothpick inserted in the center of the cake comes out clean.

Cool the cake in the pan, then serve.