Cut the pound cake into bite-sized pieces. Set aside.
Whisk the lemon pudding mix and milk together in a large mixing bowl for 2 minutes until creamy and thickened. Set aside.
In a medium mixing bowl, whisk together the mascarpone, lemon juice, and lemon zest until creamy.
Fold the mascarpone and lemon curd into the lemon pudding. Gently stir until combined. (If you overmix, the cream will get runny and run between the layers.)
Add half of the cake pieces to the bottom of a trifle bowl and spread them into an even layer. Spread half of the Cool Whip over the cake, and then spread half of the lemon pudding mixture over the Cool Whip.
Repeat the layers, being sure to press the cake to the rim of the bowl and get them nice and tight-ish at the rim, so they're visible. Then fill in the middle of the dish with the rest of the cake before adding the Cool Whip and lemon pudding.
Garnish the top with swirls of whipped cream or Cool Whip and lemon slices. You can even add some mint sprigs for color if you like. Chill in the fridge for at least 20 minutes or until ready to serve.
Notes
You can use store-bought or homemade pound cake for this trifle. The same goes for the lemon curd.
If you don't have a trifle bowl, a glass 5-quart bowl will work too. Trifles are all about showing off the different layers.