Preheat your oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
In a large mixing bowl, combine the flour, sugar, baking powder, baking soda, cinnamon, and salt.
Add the oil and eggs to the dry ingredients and mix until well combined. Fold in the grated carrots.
Pour the batter into the prepared pan and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool completely.
For the cream cheese frosting, beat the cream cheese and butter together until smooth. Gradually add the powdered sugar and vanilla extract, and beat until creamy.
For the whipped cream, beat the heavy whipping cream, powdered sugar, and vanilla extract together until stiff peaks form.
To assemble the trifle, cut the cooled carrot cake into cubes. In a trifle dish, layer the cake cubes, cream cheese frosting, and whipped cream. Repeat the layers until the dish is full, ending with a layer of whipped cream on top.
Refrigerate for at least 2 hours before serving to allow the flavors to meld together.