Chef John's Classic Peach Dessert

Combine raspberries, 1/3 cup sugar, 1 tablespoon lemon juice, water, and balsamic vinegar in a saucepan over medium heat. Heat the mixture until sugar dissolves and berries soften, approximately 2 to 3 minutes.

Transfer the mixture to a bowl and let it cool down to room temperature, then cover and refrigerate until completely chilled.

Combine 2 cups sugar, 2 cups water, 2 tablespoons lemon juice, and split vanilla bean in a large saucepan. Heat the mixture over medium heat until it reaches a simmering state, stirring occasionally.

Submerge peach halves with cut sides facing upwards in the syrup and cook until they become tender, flipping them occasionally for 5 to 8 minutes per side. Remove the peaches from heat and let them cool down in the syrup, then transfer them to a bowl. Cover the bowl with plastic wrap and refrigerate until chilled for about 4 hours.

Remove the peach skins and place each half on top of a scoop of ice cream in a serving dish. Spoon the chilled raspberry sauce over the top of each peach half, then garnish with toasted and slivered almonds.