Step 1

Slice 6 large seedless mandarin oranges (about 1½ lb.), peeled, ½" thick across the equator (about 3 slices per fruit); transfer to a 3-qt. heatproof dish.

Step 2

Combine 2 cups (400 g) sugar and 1 cup water in a medium saucepan, cover, and heat over medium, stirring occasionally, until sugar is dissolved, 4–7 minutes. Uncover and continue to cook, stirring or swirling pan occasionally, until syrup boils, then turns a deep brown color, 12–18 minutes. Remove from heat and gradually add 1 cup water (stand back—mixture will spatter and seize). Set pan over low heat and cook, stirring often, until caramel is completely dissolved, about 2 minutes.

Step 3

Pour caramel over mandarin orange slices (they should be mostly submerged). Cover dish with a plate or plastic wrap and chill until very cold, at least 2 hours and up to 2 days.

Step 4

Melt 1 Tbsp. unsalted butter in a small saucepan over medium. Add ½ cup sliced almonds and cook, stirring constantly, until golden brown, 4–8 minutes. Transfer to a small bowl, season with a pinch of kosher salt, and toss to combine. Let cool.

Step 5

To serve, scoop 2 pints vanilla ice cream into bowls and place 2–3 mandarin orange slices in each bowl. Spoon caramel sauce over and around fruit; top with toasted almonds and a pinch of flaky sea salt.