*If using unsalted butter then add 1/4 teaspoon of salt
For room temperature remove ingredients from the fridge about 30-45 minutes before using.
Pre-heat oven to 350°. Lightly grease and flour a 8 inch spring form cake pan.
In a medium bowl whisk together sugars, salt and cocoa add warm melted butter and stir to combine, add flour and mix with a fork until moist clumps appear, set aside.
In a large bowl whisk together flour, baking soda, baking powder and salt.
In a medium bowl beat butter until smooth & creamy then add sugar and continue to beat until light and fluffy, continue beating while adding egg and yolk, (one at a time), then add yogurt, milk and vanilla, add the flour mixture a third at a time beating just until mixed. Spread in prepared pan and cover cake batter with crumb topping, do not press down. Bake approximately 1 hour. Let cool. Enjoy!