Preheat Oven to 350° F
Chop or grind walnuts depending if you want larger or smaller pieces.
Next in a small bowl, combine cinnamon, walnuts, and brown sugar.
Set aside.
Prepare a Bundt Pan by greasing and flouring*
Do not let extra flour in the bundt, make sure to tap it all around, and then if any extra remains, dump it into the sink.
If your butter is not softened at this point, microwave it in 30-second increments at 50% power, not to create a liquid, rather soften.
Set aside.
In a small mixing bowl, combine flour, baking soda, powder, and set aside.
Using a large mixing bowl (or stand mixer), combine sugar, butter, eggs, and vanilla.
Mix until creamy but do not over mix.
Next, add in the sour cream.
Again, just enough to combine.
Now take the dry ingredients and add them a little at a time to the wet trying to avoid a POOF Of dust.
Just add bit by bit and then mix very well on low until well mixed.
Get your bundt pan, dust it with cinnamon, and add the 2 Tbsp of walnuts scattered around the bundt evenly.
Now, divide the cake mixture in half.
Using one half of the batter, drop by the large spoonful around the pan.
Next, divide the Cinnamon Walnut Filling in half.
Using one-half, top the newly dropped batter.
Now, cover this layer with the rest of the batter, and again, coat this with the other half of the cinnamon walnut filling.
Bake in the oven for up to 55-65 minutes - the goal is a toothpick coming out clean, it does not really turn golden brown.
Once it's fully baked and the toothpick comes out clean, allow it to cool for 20 minutes.
Then, invert and remove from pan.
Serve and enjoy.