Strawberry Vinegar

You'll get this trophy the first time you make Risotto, which happens to only occur during one Ending, which is about mid-way through the Bittersweet Goodbye Ending.

See the Platinum Walkthrough [LINK] or the Bittersweet Goodbye trophy for more details and exact steps.

When you return home from your strawberry-picking trip, they decide to make a dish out of the remaining strawberries. When Licia insists on making shortcake, stand your ground and choose the first option, "Oh, absolutely".