Preheat the oven to 350. Grease a 9-inch springform pan.
For the crumble: In a small mixing bowl, stir together the flour, brown sugar, cinnamon and sea salt. Cut in the cold butter using a pastry blender until the mixture resembles crumbs. Stir in the pecans. Set aside.
For the coffee cake: In a medium mixing bowl, stir together the flour, baking powder, baking soda, cinnamon, ginger, nutmeg, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and the brown sugar, about 1 minute on medium-high speed. Add the eggs and beat to combine, scraping the sides of the bowl as needed. Then add the pumpkin, sour cream, vanilla, and orange zest and beat until well incorporated. Pour in the flour and spices mixture you have set aside for the cake. Beat until it all comes together and forms a thick batter. Spread half of the batter into the prepared springform pan using a small offset spatula. Sprinkle half of the crumble over the batter. Then gingerly spread the rest of the batter over top. Sprinkle the top of the cake evenly with the remaining pecan crumble.
Bake for 50 minutes or until set in the middle. Allow to cool on a cooling rack for 15 minutes before releasing from the springform pan. Serve warm.