Strawberry Tiramisu is probably the best baking item to create, the recipe for it is 1 strawberry, 1 vanilla, and 1 sugar. This recipe is mentioned twice in the game:

1) If you talk about cooking with Giuseppi Mezzoalto
2) Purchasing the slip of paper from Heidi Shadows (the slip of paper has the recipe for the tiramisu as well as the Club Xizzle password) Sell the strawberry tiramisu to the grocery man in Sim Quarter and you will get over 1,000 simoleons!