My Grandmother's Elegant Layered Berry Mousse

Ingredients

• 1 cup (240 ml) heavy cream
• 1 cup (240 g) mixed berries (strawberries, blueberries, raspberries)
• 3 tablespoons (45 g) sugar
• 1 teaspoon (5 ml) vanilla extract
• 1 tablespoon (15 g) gelatin powder (or agar-agar for vegan option)
• 2 tablespoons (30 ml) water (for dissolving gelatin)
• 1 cup (240 ml) fresh mixed berries, plus extra for garnish
• 2 tablespoons (30 g) sugar
• 1 tablespoon (15 ml) lemon juice