Preheat oven to 350° Fahrenheit. Line 3 5- or 6-inch cake pans with parchment paper and spray with nonstick cooking spray; set aside.
Using a hand mixer, mix cake mix, eggs, pumpkin, coffee, butter and cinnamon together in a large bowl until combined.
Divide the batter between the prepared pans and bake 27-32 minutes until a toothpick inserted in the center comes out clean. Remove from the oven and let cool 10 minutes, then remove cakes from pans to a cooling rack to cool completely.
MAKE THE FROSTING:
Using a mixer, beat together the cream cheese and butter until creamy.
Add the brown sugar, pumpkin, and cinnamon and beat until smooth and creamy. Set aside.
MAKE THE PUMPKIN SPICE STREUSEL:
Preheat oven to 350 degrees Fahrenheit and line a baking sheet with parchment.
Combine all ingredients in a medium bowl until clumps form.
Spread on parchment lined baking sheet and bake for 5-7 minutes.
Cool completely on baking sheet.
Break up any larger chunks if needed.
ASSEMBLE THE CAKE:
Trim the domed tops off the cakes as needed. Place one layer of cake on a cake plate.
Top with a thin layer of buttercream and a sprinkling of streusel.
Repeat with the next 2 layers. The pattern should be: 1st cake, frosting, streusel, 2nd cake, frosting streusel, 3rd cake.
Spread a thin crumb coat layer of buttercream over the entire cake, smoothing it out as best as possible.
Immediately press some of the streusel on the bottom third of the cake, pressing it into the frosting.
Spread the remaining streusel on the top of the cake.
Store the cake uncovered at room temperature for up to a day. Refrigerate the cake in an airtight container after it has been cut.