Preheat oven to 350°. Spray a 9×13-inch pan with cooking spray then dust lightly with flour.
With an electric mixer, blend butter and sugar in a large bowl; set aside. Sift together flour and salt; set aside.
Mix eggs, buttermilk, vanilla, baking soda and vinegar in a separate bowl.
Alternate adding flour mixture and buttermilk mixture to butter mixture. Mix well after each addition.
In a small bowl, mix red food coloring and cocoa powder; add to the cake batter and mix until combined. Pour batter into prepared pan and bake for 30-40 minutes.
For the Syrup
In a small saucepan, bring sugar and water to boil over medium heat.
Stir to dissolve sugar completely. Stir in vanilla. Let cool.
Cut the cake in half and cut one half into chunks; brush with cooled syrup. You likely will not need more than half of the cake for the trifle.
For the Whipped Layer
In a large bowl, beat cream cheese, mascarpone and sugar on high speed until light and fluffy.
Reduce speed to medium and slowly pour in whipping cream.
Continue beating until mixture resembles soft whipped cream.
Assemble the Trifle
In the bottom of your trifle dish, arrange a single layer of red velvet cake chunks. Spoon about 1 1/2 cups of the whipped topping on top of the cake cubes. Next, sprinkle almonds and then shaved chocolate.
Keep repeating layers until you run out of room in your dish. Garnish with mint leaves and fresh cranberries.