Apple Cinnamon Coffee Cake with Streusel topping

1¼ cup All Purpose Flour
Salt, as needed
1½ tsp Baking Powder
½ cup White Sugar
¼ cup Butter
2 Eggs
½ tsp Cinnamon Powder
4 tbsp Milk
1 Large Apple (tart), peeled, cored and sliced

For topping:
¼ cup All Purpose Flour
2½ tbsp Butter
¼ cup Brown Sugar
¼ tsp Cinnamon Powder
2-3 tbsp Crushed Walnuts (optional)

Preheat oven to 345 F. Grease and flour a round baking pan.
Prepare the topping by combining brown sugar, cinnamon powder and all purpose flour well. Cut the butter into this mixture using a fork until it appears crumbly.
You can also add a few tbsps of chopped walnuts (optional). Keep aside.
Sieve all purpose flour, baking powder and salt in a bowl.
In another bowl, cream butter with sugar. Use a hand blender to make a smooth creamy mixture.
Add the beaten eggs and combine well. Add cinnamon powder and combine.
Fold in the flour mixture little by little alternating with milk. Do not overbeat; just fold the dry till there is not trace of any flour.
Pour batter into the greased and floured pan. Smooth the top using a spatula.
Arrange the apple slices on top.
Sprinkle the streusel topping liberally.
Bake in preheated oven for 1 hr or till a toothpick inserted into the cake comes out clean. Place on a wire rack to cool, slice and serve at room temperature.

Note: Combine ¼ cup all-purpose flour with ¼ oatmeal for thicker topping.