Make the crust: Combine 2 cups graham cracker crumbs, 6 tablespoons melted unsalted butter, 3 tablespoons granulated sugar, and 1/4 teaspoon salt in a small bowl. Mix until the texture resembles wet sand (about 1 minute). Press firmly into the bottom of a 9-inch springform pan, using the bottom of a measuring cup to pack it down evenly. Refrigerate for 15 minutes while you prepare the filling. Checkpoint: Your crust should be compact and hold together when pressed.

Bloom the gelatin: Sprinkle 1/2 teaspoon gelatin powder over 2 tablespoons cold water in a small microwave-safe bowl. Let it sit undisturbed for 5 minutes so the gelatin absorbs the water and becomes spongy. Checkpoint: The gelatin should look puffy and soft, not dry.

Dissolve the gelatin: Microwave the bloomed gelatin for 10 seconds on high power, stirring halfway through if needed, until completely clear and liquid (about 30 seconds total). It should feel warm, not hot—test with your finger. Set aside to cool for 3 minutes. Checkpoint: The gelatin should be translucent with no lumps, and cool enough to touch comfortably.

Prepare the cream cheese base: Remove 16 ounces cream cheese from the refrigerator 30 minutes before starting. Cut it into chunks and add to a large mixing bowl. Beat with an electric mixer on medium speed for 2 minutes until smooth and creamy. Add 1/2 cup granulated sugar and beat for another 1 minute until fluffy and light. Checkpoint: The mixture should be pale, smooth, and increased slightly in volume.

Add citrus and flavorings: Pour 1/2 cup fresh orange juice into the cream cheese mixture. Add 2 tablespoons orange zest, 1 teaspoon vanilla extract, 1/4 teaspoon almond extract, and 1/4 cup orange liqueur if using. Beat on low speed for 1 minute until fully combined. The mixture should be smooth with no streaks. Checkpoint: Everything should be evenly mixed with a smooth, pourable consistency.

Incorporate the gelatin: Pour the cooled liquid gelatin slowly into the cream cheese mixture while beating on low speed. Beat for 30 seconds until fully combined and no streaks remain. The mixture should be thick but pourable. Checkpoint: No visible gelatin lumps; the filling should be homogeneous and mousse-like.

Whip the cream: In a separate, very clean mixing bowl (any grease will prevent whipping), pour 1 cup heavy whipping cream. Beat with an electric mixer on high speed for 3 to 4 minutes, starting slow and gradually increasing speed. The cream will go from liquid to soft peaks (tips curl over when beaters are lifted) to stiff peaks (tips stand straight up). Stop when you reach stiff peaks—do not overbeat or you'll get butter. Checkpoint: The whipped cream should be billowy, thick, and hold peaks when a spatula is lifted.

Fold in the whipped cream: Add half of the whipped cream to the orange cream cheese mixture. Using a rubber spatula, gently fold by cutting down the center, scraping along the bottom, and folding over the top. Rotate the bowl and repeat 8 to 10 times until barely combined (some white streaks are okay). Add the remaining whipped cream and repeat until just combined. Fold gently—over-mixing will deflate the whipped cream and make the filling dense. Checkpoint: The filling should be light, fluffy, and mostly uniform with minimal lumps.

Fill the pan: Pour the filling into the prepared crust, spreading it evenly with an offset spatula or the back of a spoon. Smooth the top so it's level. Work quickly because the filling will begin to set. Checkpoint: The filling should be level and fully cover the crust.

Refrigerate: Place the cheesecake in the refrigerator for at least 6 hours, but preferably overnight (up to 12 hours). This allows the gelatin to fully set and the flavors to meld. The longer you chill, the firmer the texture. Do not freeze. Checkpoint: When fully set, a gentle tap on the side of the pan should show minimal jiggle in the center.

Garnish and serve: Remove the cheesecake from the refrigerator 10 minutes before serving so it's not ice cold. Run a thin, warm knife around the edges and gently release the springform sides. Top with a dollop of fresh whipped cream in the center or around the perimeter. Arrange thin orange slices and candied orange peel on top as garnish. Slice with a warm, wet knife, wiping between cuts for clean edges. Serve immediately and enjoy within 30 minutes of removal from the refrigerator for best texture. Store any leftovers covered in the refrigerator. Checkpoint: Slices should cut cleanly and hold their shape.