Nana swore by this simple 3 ingredient wonder. We thought she slaved away for hours until I finally caught her making it.

Carefully pour the mixture into the prepared glass bundt or ring mold, smoothing the top if needed. Tap the mold lightly on the counter a few times to release any large air bubbles and help the mandarins settle into a nice, suspended pattern.
Transfer the mold to the refrigerator, keeping it level. Chill for at least 4 hours, or until very firm all the way through. For the cleanest slices and best structure, overnight chilling is ideal. The surface should look glossy and set, and the center should not wobble when gently shaken.
To unmold, fill a larger, shallow bowl or your clean sink with 1 to 2 inches of warm (not hot) water. Run a thin knife or small offset spatula briefly around the top edge of the mold to loosen. Gently dip the outside of the glass bundt dish into the warm water for 10 to 15 seconds, keeping the water level below the rim so it doesn’t spill into the dessert.
Place a serving plate upside down over the mold. Firmly hold the plate and mold together, then quickly invert. Give the mold a few gentle shakes to help the sherbet ring release. Lift the mold straight up; if it doesn’t release, repeat the warm water dip in very short intervals until it slides out cleanly.
Return the unmolded sherbet ring to the refrigerator until serving time. Slice with a sharp knife dipped in warm water and wiped dry between cuts for neat wedges, showing off the glossy orange ring and suspended mandarin pieces.
Variations & Tips
For a lighter texture, you can whisk in 1 cup of thawed whipped topping or lightly sweetened whipped cream after the sherbet is fully blended and the mixture has cooled a bit; this will make the mold slightly fluffier and more mousse-like while still holding its shape. If you prefer a stronger citrus punch, stir in 1 to 2 teaspoons of finely grated orange zest along with the mandarin oranges. To lean into the vintage holiday feel, arrange a ring of extra drained mandarin segments or thin fresh orange slices on the serving plate around the base of the mold just before bringing it to the table. You can also play with the fruit: swap in canned pineapple tidbits (very well drained) for part of the mandarins, or add a handful of finely diced fresh strawberries for color, keeping the total fruit volume roughly the same so the mold still sets firmly. If your kitchen runs warm, chill the sherbet mixture in the bowl for 10 to 15 minutes, stirring occasionally, until it thickens slightly before you pour it into the bundt; this helps the fruit stay more evenly suspended instead of drifting to the top or bottom. Finally, if you don’t have a glass bundt dish, use any 6- to 8-cup mold or even a deep glass bowl—the flavor and creamy, nostalgic character will be the same, even if the shape is different.