Step 1In a medium saute pan, combine the sugar and water. Add the lemon juice and heat the pan over medium-high heat. Do not stir the pan as the sugar melts and starts to bubble; this can cause the sugar to become lumpy and crystallize. If the sugar crystallizes, you will have to start over.
Step 2Once the sugar begins to turn a rich brown, gently swirl the caramel by moving the handle of the pan. Continue to cook the caramel until it is a rich, dark brown. Keep in mind that the caramel will look darker in the pan than it actually is. Be careful not to overcook the caramel, or it will blacken and burn.
Step 3As soon as the caramel is ready, remove it from the heat and pour the caramel into a 10-inch cake pan to coat the bottom of the pan. Swirl the cake pan to coat the bottom evenly.
Step 4Place the cake pan on a flat surface and set aside until the caramel is cool.
Step 1Heat the oven to 325 degrees.
Step 2In a heavy-bottom pot, bring 2 quarts of goat milk to a simmer. Cook until it is reduced to 3 cups. Stir in 1 cup plus 2 1/2 tablespoons sugar and continue to cook until the milk is again reduced to 3 cups.
Step 3Remove the milk from the heat and strain it through a very fine strainer into a clean pot. Stir in the remaining goat milk and the heavy cream.
Step 4In a large bowl, whisk together the eggs and egg yolks. Whisk in the remaining one-half cup sugar and the milk powder. Gradually pour the hot milk mixture into the eggs to temper, whisking constantly.
Step 5Strain the mixture through a very fine strainer into the caramel-lined pan.
Step 6Prepare a hot water bath: Place the pan inside a larger roasting pan, and fill the roasting pan with hot water until the water comes halfway up the side of the cake pan.
Step 7Gently place the roasting pan in the oven and bake until the center of the flan feels barely firm and the overall flan feels slightly loose but not watery (it will jiggle), 1 hour to 1 hour and 15 minutes (do not overcook the flan; it will continue to set up as it cools). Gently rotate the pan halfway through baking for even coloring.
Step 8Remove the roasting pan from the oven, and gently remove the cake pan from the hot water bath. Place the cake pan on a rack to cool slightly, then refrigerate until cold. When the flan is cold, cover the pan tightly with plastic wrap and store until ready to serve, 2 to 3 days.
Step 9To serve the flan, unwrap the pan and gently invert the cold flan onto a large dish or cake stand, tapping the pan to remove it (if the flan won't come out of the pan, rest the pan in a large pan of hot water for a minute or two to loosen). Serve the flan with the caramel sauce.