Prep the pan: Line an 8x8-inch square pan with parchment, leaving overhang on two sides for lifting later. Lightly grease the other sides to prevent sticking.

Make the crust: In a bowl, mix graham cracker crumbs, brown sugar, and melted butter until the mixture holds together when pressed. It should feel like wet sand.

Press and chill: Firmly press the crust into an even layer in the pan, using the bottom of a measuring cup to compact it. Chill while you make the filling.

Soften the gelatin (optional): In a small bowl, sprinkle gelatin over cold water and let it bloom for 5 minutes. Then gently warm it in the microwave for 5–10 seconds until just dissolved. Let it cool to lukewarm.

Whip the cream: In a cold bowl, beat heavy cream with powdered sugar to medium-stiff peaks. Do not overwhip. Set aside.

Beat the cream cheese: In a separate bowl, beat softened cream cheese with granulated sugar, vanilla, lemon juice, and a pinch of salt until smooth and fluffy, about 2–3 minutes. Scrape the bowl as needed.

Add gelatin (if using): With the mixer on low, stream the lukewarm dissolved gelatin into the cream cheese mixture and mix just to combine.

Fold in the whipped cream: Gently fold the whipped cream into the cream cheese mixture in two additions until no streaks remain. Keep it light to preserve the airy texture.

Fill the pan: Spread the filling over the chilled crust. Smooth the top with an offset spatula. Tap the pan lightly on the counter to remove air bubbles.

Chill to set: Cover and refrigerate for at least 6 hours, preferably overnight, until firm enough to slice cleanly.

Slice and serve: Lift the bars out using the parchment. Warm a sharp knife under hot water, wipe dry, and cut into 12–16 bars. Add toppings if you like.