1. Prepare the Grapefruit:

• Wash and dry the white grapefruit.
• Grate half of the grapefruit’s peel.
• Squeeze the juice from the entire grapefruit.
• Set both the juice and grated peel aside.

2. Make the Mascarpone Cream:

• In a large mixing bowl, beat the egg yolks with 5 tablespoons of sugar using a hand mixer until the mixture turns creamy.
• Add the mascarpone cheese to the egg yolk mixture and continue to beat until well combined.

3. Incorporate Whipped Egg Whites:

• In a separate bowl, whip the egg whites until they reach stiff peaks.
• Gently fold the whipped egg whites into the mascarpone and yolk mixture.

4. Add Whipped Heavy Cream:

• In yet another mixing bowl, whip the chilled heavy whipping cream until stiff.
• Gently fold this into the mascarpone mixture.

5. Stir in Grapefruit Zest:

• Fold in the grated grapefruit peel into the mascarpone mixture, ensuring it’s well distributed.

6. Prepare Grapefruit Dip for Ladyfingers:

• In a shallow dish, combine the grapefruit juice, 1 cup of water, and the remaining 2 tablespoons of sugar.
• Stir until the sugar dissolves completely.

7. Assemble the Tiramisu:

• Lightly spread some of the mascarpone cream mixture at the bottom of your baking dish.
• Dip each ladyfinger into the grapefruit-water mixture briefly, ensuring they don’t get too soggy.
• Squeeze out the excess liquid from the ladyfingers.
• Create a layer of dipped ladyfingers in the baking dish.
• Evenly spread half of the mascarpone cream over the ladyfingers.
• Repeat another layer of dipped ladyfingers.
• Top with the remaining mascarpone cream, ensuring a smooth and even layer.

8. Chill and Set:

• Cover the tiramisu tightly with cling wrap.
• Refrigerate for at least 2 hours, allowing the flavors to meld and the dessert to set.

9. Serve and Garnish:

• When ready to serve, garnish with fresh grapefruit peels.