Preheat oven to 350°F.
In a medium-size bowl, whisk together the flour, oats, baking soda, salt, fennel seed, cinnamon, ginger and nutmeg. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, mix both oils with the sugar. Once combined, add in the eggs one at a time. Next, add the flour mixture in batches on low speed. Once fully combined, turn off the mixer and remove the bowl from the stand. Using a rubber spatula, fold in the carrots, raisins, pecans and orange zest.
Pour the batter into a prepared 9x13-inch baking pan and bake 45-50 minutes. Remove cake from oven and let cool.
For the buttermilk glaze, whisk the buttermilk with the confectioners sugar and salt in a small bowl until smooth. Pour the glaze over top of the cake and let it soak in while you prepare the frosting.
Place the cream cheese and butter into the mixer bowl and beat with a paddle attachment until smooth. With the mixer on low speed, add the confectioners’ sugar a spoonful at a time until completely incorporated. Once all the sugar has been added, add the vanilla and salt. Spoon the cake over top of the cake and then spread evenly with a spatula.