1. In a saucepan, melt the butter over medium heat. Continue cooking, swirling the pan occasionally, until the butter turns a light golden brown and has a nutty aroma. Remove from heat and let it cool to room temperature.
2. In a mixing bowl, combine the browned butter, powdered sugar, milk or cream, vanilla extract, and a pinch of salt. Beat until the mixture is smooth and fluffy.

Assembly:

1. Place one cake layer on a serving plate. Spread a layer of brown butter buttercream over it.
2. Add some pecan praline pieces over the buttercream.
3. Repeat with the next cake layer.
4. Place the final cake layer on top and cover the entire cake with the remaining buttercream.
5. Decorate the top with more pecan praline pieces.
6. Slice, serve, and enjoy your Pecan Praline Chocolate Spice Cake with Brown Butter Buttercream!

This cake is a delightful blend of flavors and textures that will impress your guests and satisfy your sweet cravings.