Cinnamon Streusel Coffee Cake (คอฟฟี่เค้กไส้สเตรอเซิลซินนามอน)

1.Preheat the oven to 180°C (350°F), conventional top and bottom heat. Grease a 9–10 inch Bundt pan lightly with baking spray and set aside.

2.Prepare the streusel filling: In a bowl, combine butter, shortening, flour, brown sugar, cinnamon, and salt. Use a pastry cutter or your fingertips to rub the mixture until it resembles small crumbs. Fold in the chopped walnuts and set aside.

3.Sift together flour, baking powder, baking soda, and salt. Set aside.

4.In a mixing bowl, cream the butter, shortening, and sugar until light and fluffy. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

5.Reduce the mixer speed to low. Add the dry ingredients in three additions, alternating with the sour cream. Mix just until combined after each addition.

6.Pour one-third of the batter into the prepared pan. Sprinkle half of the streusel filling over the batter. Add another third of the batter, followed by the remaining streusel. Finish with the remaining batter on top.

7.Bake for about 32 minutes, or until a toothpick inserted into the cake comes out clean. Let the cake cool in the pan for 10 minutes before turning it out onto a wire rack. Allow it to cool completely, then dust lightly with icing sugar before serving.