Creating this incredible Blueberry Crumb Cake involves a few simple steps. Follow this guide for best results:

1. Preheat the Oven: Begin by preheating your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.

2. Prepare the Batter: In a large mixing bowl, cream together the softened butter and sugar until light and fluffy.

3. Add Eggs: Beat in the eggs one at a time, fully incorporating each before adding the next.

4. Incorporate Milk and Vanilla: Add the whole milk and vanilla extract into the mixture, mixing until smooth.

5. Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add this dry mixture to the wet ingredients, stirring until just combined.

6. Fold in Blueberries: Gently fold in the fresh blueberries, being careful not to overmix.

7. Prepare the Crumb Topping: In another bowl, combine the flour, sugar, and ground cinnamon. Add the cold cubed butter and mix with your fingers or a pastry cutter until the mixture resembles coarse crumbs.

8. Assemble: Pour the batter into the prepared baking pan, spreading it evenly. Sprinkle the crumb topping generously over the batter.

9. Bake: Place the pan in the preheated oven and bake for 40-45 minutes, or until a toothpick inserted in the center comes out clean.

10. Cool: Once baked, remove the cake from the oven and allow it to cool in the pan for about 15-20 minutes before slicing.