Preheat oven to 350 degrees F. Line a brownie pan with parchment.
In a bowl, add all the dry ingredients and whisk well.
Add the wet ingredients to the bowl and mix to just about combine. Let it sit for 2 minutes, then mix again to ensure there are no dry flour streaks.
Pour the thick batter into the brownie pan. Even it out using a spatula.
Make the Streusel by mixing everything in a bowl with your fingers or a spoon until crumbly. Add a tsp or so more oil if needed.
Sprinkle all over the cake and evenly spread.
Bake the cake for 40 to 45 minutes. Test with a toothpick from the center.
Cool completely before slicing. Serve with turmeric pumpkin spice latte. For a decadent dessert, add a light drizzle of plain sugar icing.
