How to Make It
In a medium bowl, whisk the eggs with 3/4 cup of the sugar until combined. In a small saucepan, warm the lemon zest, lemon juice, olive oil, cocoa butter and the remaining 3/4 cup of sugar over moderate heat, stirring to dissolve the sugar. While whisking constantly, slowly drizzle half of the lemon juice mixture into the eggs. Add the egg mixture to the saucepan and cook the curd over moderately low heat, stirring constantly, until thickened and a candy thermometer inserted in the curd registers 186°, about 12 minutes.
Strain the curd through a fine sieve into a blender. Puree until lightened, about 1 minute. Scrape into a bowl. Press a sheet of plastic wrap directly on the curd and let cool to room temperature. Refrigerate until cold and set, about 2 hours.
Spread the lemon curd on the toasts and top with blackberries. Garnish with toasted coconut and serve.
Solid cocoa butter is available at natural food shops, Whole Foods and amazon.com.