Preheat the oven to 315 degrees F. Spray a tube pan with with nonstick baking spray OR use a pastry brush to coat the pan in butter and add 2-3 tbsp of flour. Coat the entire pan in the flour and tap off any excess flour. Set aside.
Start by mixing the dry ingredients – In a large bowl, combine cake flour, baking soda, nutmeg, and kosher salt together in a bowl. Whisk together and set aside.
Add butter, butter flavored shortening, and sugar to the bowl of a stand mixer fitted with the paddle attachment. Cream butter mixture on medium speed for 7 minutes, scraping down the sides of the bowl with a rubber spatula midway through.
Reduce mixer to low speed. Begin adding eggs, one at a time, ensuring that each egg is fully incorporated prior to adding the next. Then add in the almond extract and butter vanilla emulsion (you can also use vanilla extract). Scrape down the sides of the bowl again and continue to mix on low for an additional 15-20 seconds, until all ingredients are fully incorporated and the mixture looks fluffy.
Add half of the flour mixture to the bowl, mix until just combined, about 15 seconds. Then pour in the buttermilk and amaretto. Continue to mix on low speed until combined, about 10 seconds. Add the remainder of the dry ingredients and mix until combined, about 20 seconds. Scrape down the sides of the bowl once more, ensuring to scrape all of the way down to the bottom of the bowl, making sure that all of the batter is mixed together.
Pour the cake batter to the prepared bundt pan. Bake for 1 hour and 25-35 minutes, until a skewer inserted into the center of the cake comes out clean or with just a few moist crumbs. Allow the cake to cool in the pan for 10 minutes, then turn over to cool completely on a wire rack.
Once the cake has cooled, make the almond glaze. Combine melted butter and powdered sugar and whisk together until thickened. Then pour in whole milk, almond extract, and vanilla extract and mix until combined. Pour on top of the cake and serve.
Drizzle on top of the cooled cake then garnish with sliced almonds.
Notes
Make sure that all of the ingredients are at room temperature! This includes the eggs, buttermilk, butter, shortening, and even the amaretto. This allows for the batter to comes together without splitting/curdling.
Cream the butter and sugar properly! Beat until pale and fluffy (at least 5-7 minutes). This helps dissolve the sugar and also incorporates air into the batter which helps the cake rise while baking.
Use a kitchen scale to measure your ingredients! This prevents you from adding too much flour and yields the most consistent bakes (measuring cups are so unreliable). I swear by this! (you can find the metric measurements in the recipe card)
Scrape the bowl often! This keeps ingredients evenly mixed and prevents streaky, unmixed batter.
Substitution Notes
If you don't have or don't want to use vegetable shortening, sub it out for 1 additional stick of butter (1/2 cup ~ 113g).
No amaretto? Use more buttermilk in its place (1/4 cup ~ 60g more to be exact).