In a mixing bowl, combine the brown sugar, granulated sugar, cinnamon, nutmeg, pecans, and flour. Pour in the melted butter and mix until crumbly. Set aside. Easy as pie—or should I say, cake?
In a large bowl, cream the softened butter and sugar together until light and fluffy. Add the eggs, one at a time, and mix in the vanilla extract and lemon zest. Pour in the sour cream and lemon juice, mixing well until everything is combined.
In another bowl, whisk together the flour, baking powder, baking soda, and salt. Gradually add this dry mixture to the wet ingredients. Stir until just combined. Be careful; overmixing can make your cake dense.
Gently fold in the blueberries. The trick here is to be patient—this helps maintain the integrity of those juicy berries.
Spread the batter in a prepared baking pan. Use a spatula to even it out. Then, crumble the streusel topping over the batter. Prepare to be dazzled as it bakes.
Pop the baking pan into a preheated oven at 350°F (175°C). Let it bake for about 45–50 minutes, or until a toothpick inserted into the center comes out clean.
Once out of the oven, let the cake cool for about 20 minutes. A quick dusting of confectioners’ sugar will make it look divine.