Preheat oven to 350F. Line a 9-by-10-inch baking pan with parchment paper so the edges of parchment paper stick up (this way you can lift the bars out to cut when they are done); set aside.
In a medium sized bowl make the crumb topping by mixing together the flour, cinnamon, sugars and melted butter in a bowl. Combine the mixture with a spoon until it has formed crumbs. Set aside.
In a large bowl, whisk the brown sugar, eggs, and vanilla until smooth.
Pour the melted butter into the brown sugar mixture and whisk until smooth (make sure the melted butter isn’t very hot, or it may cook the eggs)
Add the flour, baking powder, cinnamon, nutmeg and salt and stir until just combined, don’t overmix.
Fold in the diced apples, pecans and candied ginger.
Spread the batter out into prepared pan, smoothing the top lightly with a spatula. Then sprinkle the crumb topping evenly over the top.
Bake for about 20 to 25 minutes, or until bars have firmed up in the center and edges are set. The center will still be gooey, but not raw.
Allow bars to cool in pan for at least 30 minutes, then transfer to the fridge for another 20 minutes before cutting.
Cut the cooled bars into squares and serve.