Preheat oven to 375˚F. Heat 8" cast iron skillet on the stove on medium heat.
Whisk together the flour, sugar, baking powder, baking soda, salt, and spices in a mixing bowl.
Whisk together milk and flax meal in a separate bowl or liquid measuring cup until frothy. Whisk in orange juice and zest, oil and vanilla.
Peel, core and thinly slice the pear and set aside.
Stir the wet mixture into the dry mixture with a rubber spatula until just incorporated into a smooth batter. Don't over-mix the batter.
Add a tablespoon of oil or pat of butter to the hot skillet and swirl the pan to coat the bottom,.
Pour cake batter into the skillet and gently shake the pan to help the batter spread out. The batter should sizzle. Arrange pear slices on top of batter and sprinkle with reserved tablespoon of rapadura sugar.
Bake the cake on the center rack at 375˚F for 35 minutes, until it's golden brown on top, the cake comes away from the sides of the pan and a tooth pick comes out clean when inserted into the center of the cake.
Allow the cake to cool in the pan for 10 minutes and then serve it warm or at room temperature.