Line a 9X13 baking dish with parchment paper and spray the paper with a non-stick cooking spray.
Beat together the butter, brown and sugar in a large mixing bowl with a hand held mixer or stand up mixer. Add in the eggs and vanilla extract. Mix until well combined.
In a separate bowl, stir together the flour, baking powder, cinnamon and salt.
Then stir in the flour mixture into the butter/sugar mixture by hand until just combined. Do not over mix.
Press this mixture into an even layer in the baking dish. Stir together the topping ingredients and sprinkle it on top.
Bake for 25-30 minutes until a toothpick inserted into the center comes out clean.
Allow to cool completely and then cut and enjoy!
Notes
Store the leftovers in an airtight container for up to 4-5 days.