best cinnamon coffee cake

When Izy and I first started e-mailing, I asked her what the best thing she ever baked was.
She sent me the recipe for this coffee cake. 

 I can’t believe that I didn’t make this coffee cake until now (the recipe has been floating around my kitchen counter for months). But I can believe that this is the best coffee cake I have ever eaten. 

It is a rich, golden cake swirled with sweet ribbons of cinnamon, and topped with a crumbly cinnamon streusel.  I wish you could have smelled my kitchen when it came out of the oven. It smelled like heaven as the warmth of cinnamon and butter filled my house.

With love,
Erica

Streusel Topping
1 cup all purpose flour
1 cup packed light brown sugar
1 ¼ tsp cinnamon
½ cup butter, softened

Cinnamon Sugar
1/3 cup light brown sugar
¾ tsp ground cinnamon

Cake
¾ cup butter, softened
1/3 cup packed light brown sugar
½ cup granulated sugar
2 eggs
1 tbsp vegetable oil
1 ½ tsp vanilla extract
2 cups all purpose flour
1 tsp baking powder
¼ tsp baking soda
¼ tsp salt
1/3 cup buttermilk (yoghurt works too)
1/3 cup milk

1.        Preheat oven to 325 degrees F.
2.        Make topping by combining the flour with the brown sugar and cinnamon in a medium bowl. Mix in the softened butter and use your hands to combine until the mixture is crumbly and has the consistency of moist sand.
3.        Make the cinnamon sugar that will go in the middle of the cake by combining the light brown sugar with the cinnamon in a small bowl.
4.        In a large bowl, cream the butter and sugars with an electric mixer for 1 minute. Add the eggs, oil and vanilla and mix until fluffy. Add the buttermilk and milk and mix well.
5.        In a separate bowl, combine the flour, baking powder, baking soda and salt. Combine this dry mixture with the wet mixture and mix well.
6.        Spoon half the mixture in a 9 x 13 inch greased, floured baking pan. Sprinkle cinnamon sugar over the batter and pat it down into the batter. Spread the rest of the batter over the cinnamon-sugar (you may need to moisten your hands with warm water/ oil to be able to spread it out)
7.        Sprinkle on the streusel topping evenly over the batter.
8.        Bake for 50-55 minutes or until the edges just begin to turn light brown. Cool and slice into 12 pieces.