To prepare the cake:

1. Preheat the oven to 350. Lightly grease three 6” round pans and cut out parchment paper rounds to fit into the bottom of them. Set aside.
2. In a large bowl or the bowl of a stand mixer, cream together the butter, canola oil, sugar, and brown sugar until smooth, about a minute and a half. Add the egg and yolk and stir until combined. Scrape the sides of the bowl and stir in any unincorporated bits. Add half of the cake flour, the baking powder, baking soda, and salt and stir on low to combine. Add ¼ cup of the milk as well as and vanilla. Stir on low. Add the remaining cake flour and milk and stir on low just until combined. Fold in any unincorporated bits. Divide the batter evenly into the prepared pans and bake in the middle of the oven for about 22-25 minutes or until the cake has puffed, turned golden, and a toothpick inserted just barely comes out clean. Don’t overbake! Set aside to cool completely.

To prepare the pecans:

1. Preheat the oven to 325 degrees Farenheit. Line a large rimmed baking sheet with foil and lightly grease with cooking spray. Set aside.
2. In a small bowl, combine the sugar, salt, and cinnamon. In a separate bowl, stir together the butter and vanilla and then toss in the pecans. Add the sugar mixture and toss to evenly coat the nuts. Spread the nuts out on the baking pan and bake for about 20 minutes, stirring every 10 minutes. Once dry and aromatic, remove from the oven and allow to cool completely. Store in an airtight container until ready to serve. 

To prepare the buttercream:

1. In a small saucepan, dice ½ cup (4 ounces) of the butter and place on medium-low heat. Allow the butter to melt, sizzle, and begin to foam, stirring regularly all the way. Once the butter begins to bubble, stay next to the pan, stirring all the while, and watch as the buttercream turns pale golden to a fragrant amber-colored mixture. Remove from heat, being sure not to burn the butter, and place in a heat-safe bowl to cool to room temperature. Once cooled, add the brown butter to the bowl of a stand mixer and add in the remaining butter. Cream on medium speed until smooth, about one minute. Add the powdered sugar, vanilla, and salt and stir to combine. Add the cream and whip for 1 minute to fluff up.

To assemble the cake:

1. Use a serrated knife to trim the domed top off of the cakes. Chop about ¾ cup of the pecans. Add the frosting to a large piping bag fitted with a large round tip. Pipe rounds of frosting all over the top of the first cake and sprinkle pecans on top. Repeat this process with the remaining two layers, stacking the cake as you go. Serve and enjoy!