How to Make It
Preheat the oven to 350°. Lightly oil six 4-ounce ramekins. On a rimmed baking sheet, toast the almonds until golden, about 7 minutes. Let cool, then coarsely chop.
In a small saucepan, warm the half-and-half. Stir in the sugar until dissolved. Pour the mixture into a blender, add the almonds and blend until the mixture is very thick and smooth. Strain the mixture through a fine strainer set over a medium stainless steel bowl, pressing hard on the solids with a rubber spatula. You should have about 1 1/2 cups liquids. Stir in the almond extract.
In a small saucepan, sprinkle the gelatin over the water and let stand until softened, about 5 minutes. Set the saucepan over low heat and when the water is warm, remove from the heat and swirl the pan to dissolve the gelatin. Scrape the gelatin into the almond milk. Set the stainless steel bowl over an ice water bath and stir the mixture often until it begins to thicken, about 10 minutes. In a large, stainless steel bowl, beat the heavy cream until softly whipped. Fold the whipped cream into the almond mixture and spoon it into the prepared ramekins. Cover and refrigerate until the blancmanges are set, at least 4 hours or overnight.
Set an ice water bath next to the stove. Using a sharp paring knife, make an X on the bottom of each nectarine. In a medium saucepan, bring water to a boil and add the peaches. After 10 seconds, transfer the peaches to the ice water until they are cool enough to handle. Rub off the skins then pit and quarter the nectarines. Wipe out the saucepan.
In the saucepan, combine the Sauternes, water and sugar and bring to a boil to dissolve the sugar. Add the nectarines and simmer over low heat, stirring occasionally, until tender, 3 to 8 minutes, depending on the ripeness of the fruit. Remove from the heat and let cool to room temperature.
Run a small knife around the edge of each ramekin, and loosen the blancmanges by dipping the bottoms of the ramekins into a bowl of hot water. Unmold the blancmanges onto plates. Spoon the nectarines and Sauternes syrup around each blancmange and serve.