Heat oven to 350°F. Grease a 9-inch square pan and line with parchment.
Make streusel: Stir flour, sugars, cinnamon, and salt. Cut in butter until clumpy. Fold in pecans. Chill.
Beat cream cheese and sugar until smooth. Mix in egg and vanilla until silky. Set aside.
Whisk flour, baking powder, baking soda, and salt for the batter in a bowl.
Cream butter and sugar until fluffy. Beat in eggs one at a time, then vanilla.
Mix in sour cream. Add dry ingredients alternately with milk, stirring just to combine.
Spread half the batter in the pan. Pour cream cheese layer over. Sprinkle one-third streusel.
Dollop remaining batter on top and gently spread. Cover with remaining streusel.
Bake 42–48 minutes, until golden and a tester has moist crumbs. Cool 20 minutes.
Notes
For a fruity twist, fold 1/2 cup fresh blueberries into the cream cheese layer or swap pecans with walnuts. Store covered in the fridge for up to 4 days; warm slices briefly in the microwave for the just-baked feel. This cake also freezes well for 2 months—wrap slices tightly.This recipe is an original creation inspired by classic Cream Cheese Coffee Cake Delight flavors. All ingredient ratios and instructions are independently developed.