Preheat the oven to 325 degrees fahrenheit. Spray a 9 by 13 pan.
In a medium sized bowl, whisk together the 3 cups of flour, baking soda, and salt.
In the bowl of a stand mixer (or a large bowl), cream the butter and sugar on medium-low speed until just combined. Mix together no longer than 60 seconds. Mixture should look more like a paste rather than whipped). Scrape down the bowl as needed.
Add the eggs one at a time, mixing on low speed and scraping down the bowl between each one. Add vanilla and mix.
Alternate adding flour mixture and sour cream to the mixing bowl - Start by adding about ⅓ of the flour mixture (no need to measure) and mix on low speed until just mixed. Scrape down the sides of the bowl and add about half of the sour cream. Continue with another ⅓ of the flour mixture, the other half of the sour cream, and then the remaining flour. Mix on low speed until just mixed and scrape down the bowl between each addition.
In a small bowl, mix chopped pecans, brown sugar, cinnamon, and 1 ½ teaspoons flour to make the filling.
Place half of the batter in the prepared pan (about 787 grams), spread around the pecan/brown sugar filling, then top with the remaining batter. Use a spatula or the back of a fork to evenly spread each layer of batter.
Bake cake for 45-50 minutes until the top is starting to brown and a toothpick in the center comes out clean (or with just a couple crumbs).
Cool the cake in the pan for about 30 minutes.
When there are a few minutes remaining, start mixing the glaze. In a small bowl, use a hand mixer or whisk to mix the powdered sugar, milk, and vanilla.
Spread the glaze evenly over the top of the cake and let it sit for 10 minutes to solidify before eating. Enjoy!
Notes
A light metal pan was used to bake the cake. A glass pan can also be used but may take a few minutes longer.
Remember that the sour cream, butter, and eggs should be room temperature before starting.
It is really important to always mix the ingredients on low speed - we don’t want to add a lot of air to the batter.This cake has a little bit more of a dense crumb - like a pound cake.
The glaze was added to the cake after it had been out of the oven for about 30 minutes. It should be warm to the touch but not super hot.We want it to help spread the glaze evenly but we don’t want a lot of the glaze to melt into the cake.If you don’t want to spread the glaze over the cake, you could drizzle it over the top instead.