1. Macerate the berries In a large bowl, combine the mixed berries, granulated sugar, and lemon juice. Toss gently with a spatula to coat. Let sit at room temperature for 20–30 minutes, stirring once halfway. The berries will release a deep crimson syrup that smells like a farmers' market in July. Resist the urge to rush this step—it's the foundation of the entire dessert.
2. Prepare the cream cheese layer In a separate large bowl, beat the softened cream cheese with an electric mixer on medium speed until smooth and fluffy, about 2 minutes. Add the powdered sugar and vanilla, and beat until combined. Scrape down the bowl. In a small bowl, whisk together the instant pudding mix and cold milk for 2 minutes until thickened. Fold this pudding into the cream cheese mixture until no streaks remain.
3. Fold in the whipped topping Gently fold the Cool Whip (or fresh whipped cream) into the cream cheese–pudding base. Don't overmix—you want it light and airy, like a cloud. The sound of the spatula cutting through the cream should be soft and smooth. If using fresh cream, whip it to stiff peaks first, then fold in the same way.
4. Start layering Spoon half the macerated berries (including the syrup) into the bottom of a 3-quart trifle bowl or glass dish. The berries should form a juicy, crimson blanket. Top with half the angel food cake cubes, pressing them down gently so they soak up the berry liquid. You'll see the white cake blush pink as it absorbs the syrup.
5. Add the cream layer Spread half of the cream mixture over the cake cubes. Smooth it evenly—aim for a layer about 1 inch thick. It will look like a thick cheesecake filling studded with bits of berry juice.
6. Repeat the layers Layer the remaining berries and syrup, then the remaining cake cubes, then the final half of the cream mixture. Use a spatula to reach the edges of the bowl so the layers are clearly defined.
7. Chill and set Cover with plastic wrap and refrigerate for at least 1 hour. This is non-negotiable—the cake needs time to absorb the juices, and the cream layer needs to firm up. For best results, let it sit 4 hours or overnight. The texture transforms from loose to perfectly sliceable.
8. Garnish before serving Just before bringing it to the table, top with the reserved whole berries and fresh mint leaves. The contrast of bright fruit against the pale cream is what makes people gasp.