LIME PREP: Cut the lime not exactly in half, but about 1/3 of the bottom part off. cut the smaller section in quarters and reserve, wrapping in plastic wrap. To the 2/3 section, zest 1/2 teaspoon of zest, then using a fork, push the tines up into the meat and squeeze and twist the lime over a small glass to get the juice out. Discard and just reserve the juice.
YOLK MIXTURE: In a small saucepan over medium high heat, melt the butter. Add the sugar, flour, and cornstarch, stirring to incorporate. Slowly whisk the warm heavy cream into the mixture. Bring to a boil, and reduce to low heat, stirring constantly, simmer until thick enough to coat the back of a spoon.
Mix egg yolks into a medium sized bowl until light and fluffy. When the heavy cream mixture is ready, slowly whisk it into the egg yolks a little at a time to temper them. Cover and allow to cool to room temperature.
Stir in lime zest, lime juice, and vanilla into the yolk mixture and set aside.
WHITES MIXTURE: In a separate bowl, beat the egg whites, sugar. and salt at high speed with an electric mixer until soft peaks form. Gently fold the whipped whites into the cooled egg yolk mixture.
Preheat oven to 375°F Spray the insides of the ramekins with spray butter. Divide the souffle batter among the ramekins. Bake until puffed and lightly browned, about 30-35 minutes. Top with toasted coconut and garnish each with the wedges of lime. Serve warm or chilled.