Line an 8x4 inch loaf pan with plastic wrap, leaving overhang for easy removal. Place the pan in the freezer to chill.

In a large mixing bowl, whip the heavy cream with 2 tablespoons of sugar until soft peaks form (about 3-4 minutes). Do not overwhip. Refrigerate until needed.

In a medium bowl, whisk egg yolks with remaining sugar, honey, vanilla extract, and salt until the mixture becomes pale and thick (about 3-4 minutes of vigorous whisking).

If using fruit puree, strain it through a fine mesh strainer to remove seeds, then gently fold it into the egg yolk mixture along with lemon juice.

Using a rubber spatula, gently fold one-third of the whipped cream into the egg mixture to lighten it. Then carefully fold in the remaining cream in two additions, maintaining the airy texture.

Pour the semifreddo mixture into the prepared loaf pan, smoothing the top with a spatula. Tap gently to release air bubbles.

Cover tightly with the plastic wrap overhang, then add an additional layer of plastic wrap to prevent ice crystals. Freeze for at least 4 hours or overnight until completely firm.

To serve, remove from freezer and let sit at room temperature for 5-8 minutes to soften slightly. Lift out using plastic wrap and slice with a warm knife into 6 portions.