Explanatory note: This quest is not in the game HKO as of 2011 anymore. This entry describes a Beta-quest of 2008.
You can still cook/bake strawberry cake in HKO in 2011 though: to make 2 strawberry cakes you'll need: 4 basic cake, 10 mulberry, 15 strawberry (which will cost HKO-$ 180 + seeds for planting strawberries). Strawberry cake can heal 35 energy + 35 action. It needs lvl 5 to be baked and a guide of lvl 5 from the food merchant in London for HKO-$ 275.
Learned from Strawberry cake guide.