To infuse cakes with more flavor, do as pastry chefs have long done and douse them with a simple syrup after they come out of the oven. Poking holes all over the cake before doing so ensures the maximum reward for your efforts. In this recipe, a lime and honey cake is soaked with a lime and honey syrup that also includes passion fruit, for more tropical tastes. The cake itself is a marvel of moistness thanks to the eggs, brown sugar, and plain yogurt.