1 pound peaches, peeled and pitted fresh or thawed frozen with juices
2/3 cup (5 1/4 ounces | 150 grams) sugar
1 tablespoon freshly squeezed lemon juice
1/4 cup water
1 teaspoon unflavored gelatin powder
2 tablespoons peach liqueur or schnapps
1 cup heavy cream
1. Combine the peaches, sugar, lemon juice, and water in a medium saucepan. Bring to a boil, reduce the heat to medium-low, and simmer until the fruit is soft. Transfer to a blender or food processor and puree until smooth. Be careful with blending hot liquid. Measure out 1 cup of peach puree and set aside for garnish. Transfer the remaining peach puree into a large bowl.
2. Soak the gelatin in the remaining 2 tablespoons peach liqueur in a small heatproof bowl for about 5 minutes. Microwave on low for 10 to 15 seconds to heat, and stir to dissolve the gelatin. Whisk the gelatin mixture into the peach puree in the large bowl.
3. In a large bowl, whip the cream until stiff peaks form. Fold the whipped cream into the peach puree with a rubber spatula. Refrigerate the peach mousse until ready to use.