Add the butter and brown sugar to a medium bowl. Mix together with an electric mixer on high speed until combined.

Add in the flour, pumpkin pie spice and salt and mix together until the mixture resembles coarse crumbs.

Pop the streusel in the fridge to chill while making the coffee cake batter.

Preheat the oven to 350°F. Grease a 9x9 inch metal baking pan and line it with parchment paper.

In a medium bowl, whisk together the flour, pumpkin pie spice, baking soda, and salt. Then set aside the flour mixture.

Add the softened butter and granulated white sugar to a large bowl. Cream together for 2 minutes with an electric mixer on high speed.

Then add in the eggs and vanilla and mix on medium speed until pale in color and smooth, about 1 minute.

Add in the buttermilk and canned pumpkin puree and mix on medium low speed until combined. (The batter will look curdled at this point but don't worry. It will pull together once the dry ingredients are added.)

Add the dry ingredients to the pumpkin mixture and mix on medium low speed just until the batter is combined. Scrape the sides of the bowl with a rubber spatula as necessary.

Pour the batter into the prepared baking pan. Sprinkle the chilled streusel on top of the batter, making sure to cover the entire top.

Bake the coffee cake for 60-70 minutes, or until a toothpick comes out clean from the center with only a few moist crumbs. (If the top is getting too brown towards the end of the baking time, loosely cover with aluminum foil.)

Let the cake cool in the pan on a wire rack until cool enough to handle.

While the cake cools make the cream cheese drizzle by adding the cream cheese and maple syrup to a small bowl. Mix with an electric mixer on medium high speed until smooth.

Then sift in the powdered sugar a little at a time, mixing on low speed, until all is combined. Lastly, mix in the milk.

When the cake is cool enough to handle, gently pull up on the parchment paper to release the cake from the pan. Drizzle the cream cheese frosting on top of the cake, then serve.