Have ready 8 individual 5-ounce ramekins. In a thick sided heavy duty pot, combine the sugar, corn syrup, 1/2 cup of the water, and lemon juice. Cook over high heat until a medium brown caramel forms. Remove from heat and stir in the remaining 1/2 cup of water. Pour about 1 tablespoon of caramel into each ramekin.
To make the flan:
Preheat the oven to 325 degrees F.
Cream together the eggs, egg yolks, and sugar in bowl. In a medium saucepan over medium-high heat, bring the half-and-half and vanilla bean to a scald. Gradually whisk the half-and-half mixture into the eggs, a little at a time at first and whisking constantly, to temper the egg mixture.
Fill each ramekin almost to the top with the egg mixture. Set the ramekins in a deep baking dish and fill the dish with hot water that reaches halfway up the sides of the ramekins. Bake until the flan is set (jiggly but not firm), about 90 minutes. Let cool and refrigerate.
To serve, use a paring knife to cut around the outside of the ramekin and then invert the mold over each serving plate. It may be necessary to shake the flan or gently push it back on one side in order to get the flan to break loose from the ramekin. Serve with the liquid caramel that pours out as a sauce.
This recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.