Melt butter, set aside.

In a medium bowl, mix the flour, sugars and cinnamon.

Slowly pour the melted butter in as you stir the mixture with a fork. Start with 3-4 Tablespoons and add more until it looks like crumbles, without mixing too much, as overworking it will make it like a dough. Add in chopped pecans, walnuts or oats for a bit of crunchiness if desired (1/2 cup to 1 cup of each or a combination).

Refrigerate until ready to use.

To start, turn the oven on to 375°F and put the oven rack in the middle. Use butter or cooking spray to grease a 9-inch square pan.

In a medium bowl, mix together the flour, baking powder, and salt. Set it aside.

In a large mixing bowl, use an electric mixer to beat the butter and sugar until it is smooth and creamy. This takes about 2 minutes.

Add the eggs one at a time, mixing well after each one. Use a spatula to scrape the sides of the bowl.

Add the vanilla extract and mix together.

Gradually add the flour mixture, alternating with the milk, beating gently. Then add the berries and fold in gently, making sure to not over-mix.

Put the batter in the pan and spread it out evenly. Sprinkle the crumble topping on top. Bake for 40-45 minutes until it looks golden brown and a toothpick comes out clean when you poke it in. Let it cool on a rack for about 20 minutes before serving from the pan.

To enjoy this cake at its freshest, eat it on the same day it's made. Save the leftovers for a few days by wrapping the coffee cake in foil ir place in an airtight container at room temperature.