Let’s build this impressive dessert stage by stage:

1. Make the Red Velvet Cake Layers:

• Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans, lining the bottoms with parchment paper.
• In a large bowl, whisk together flour, granulated sugar, baking soda, cocoa powder, and salt.  
• In a separate medium bowl, whisk together buttermilk, oil, eggs, vanilla extract, white vinegar, and red food coloring until well combined.
• Gradually add the wet ingredients to the dry ingredients, mixing on low speed (or by hand) just until smooth and combined. Do not overmix.
• Divide the batter evenly between the two prepared pans.
• Bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean.  
• Let cakes cool in pans for 10 minutes, then invert onto wire racks, remove parchment, and let cool completely.  

2. Make the Butter Pecan Cheesecake Layer:

• Reduce oven temperature to 325°F (163°C). Grease a 9-inch springform pan (lining bottom with parchment optional but helpful).
• In a large bowl using an electric mixer, beat the softened cream cheese, granulated sugar, and brown sugar on medium speed until completely smooth and creamy, scraping down the sides.
• Add the room temperature eggs one at a time, beating on low speed just until incorporated after each addition.
• Stir in the vanilla extract and the melted (and slightly cooled) butter.
• Gently fold in the 1 cup of toasted pecans.
• Pour the batter into the prepared springform pan and smooth the top.
• Bake for 30–35 minutes, or until the edges are set and the center is almost set (it should still have a slight wobble).
• Turn off the oven, crack the oven door, and let the cheesecake cool slowly in the cooling oven for 1 hour.
• Remove from oven, let cool completely at room temperature, then cover and refrigerate for at least 2 hours (preferably 4+ hours or overnight) until thoroughly chilled and firm.

3. Prepare the Cream Cheese Frosting:

• In a large bowl, beat the softened cream cheese and softened butter together with an electric mixer until smooth and creamy.
• Gradually add the sifted powdered sugar, mixing on low speed until incorporated.
• Beat in the vanilla extract. Increase speed to medium-high and beat until light and fluffy, about 2-3 minutes. If too thick, add milk/cream 1 tsp at a time.

4. Assemble the Cake:

• Level the cooled red velvet cake layers with a serrated knife if needed (reserve crumbs for garnish).
• Place one red velvet cake layer on a serving plate or cake board. Spread a thin, even layer of cream cheese frosting over the top (about 1/2 to 3/4 cup).
• Carefully remove the chilled cheesecake from the springform pan (release sides, slide off bottom or use parchment overhang). Gently place the cheesecake layer centered on top of the frosted red velvet layer.
• Spread another thin, even layer of cream cheese frosting over the top of the cheesecake layer.
• Place the second red velvet cake layer on top (bottom-side up for a flat surface).

5. Frost the Exterior:

• Apply a thin “crumb coat” of frosting over the entire cake (top and sides) to seal in crumbs. Chill for 30 minutes.
• Apply the remaining cream cheese frosting smoothly over the top and sides of the cake using an offset spatula or bench scraper.

6. Decorate:

• Gently press the reserved red velvet cake crumbs and the ½ cup of toasted pecans onto the sides or top border of the cake for decoration.

7. Chill and Serve:

• Refrigerate the assembled cake for at least 1 hour before slicing to allow the frosting to set and flavors to meld.
• Slice with a large, sharp knife (dipped in hot water and wiped clean between cuts) and serve chilled.

Take your time with chilling and assembly for the best results