If you want a festive rim, pour 1 tablespoon corn syrup into a shallow dish. Place 1 tablespoon crushed candy cane on a separate plate. Dip the lip of a chilled tall glass into the corn syrup, then immediately into the crushed candy cane, pressing gently so the candy adheres. Set the glass aside in the fridge to firm for 5 minutes.

Make the Shake Base

In a blender, combine 3 cups vanilla ice cream, 1 cup whole milk, 1 teaspoon vanilla extract and 1 tablespoon granulated sugar. Blend on medium until smooth, about 20–30 seconds. Scrape down the sides once to ensure even mixing.

Add 1 tablespoon cranberry sauce and 1 ounce raspberries (if using) to the blender. Blend briefly (10–15 seconds) until the fruit is incorporated but the mixture still has a slightly marbled red swirl. If using whole cranberry sauce with large bits, pulse until mostly smooth.

Add 2 drops red gel food coloring and 1 teaspoon green peppermint syrup. Pulse 2–3 times to distribute color and flavor evenly. Taste and adjust: for a sweeter, more cranberry-forward flavor add another 1 teaspoon cranberry sauce; for more mint, add another 1/2 teaspoon peppermint syrup (or 1/2 teaspoon mint liqueur for adults). Note: food coloring is optional; the cranberry will provide red tone.

If the shake is too thick, add up to 2 tablespoons more milk and pulse to reach desired pourable consistency. The ideal shake should be thick enough to hold whipped cream on top but thin enough to sip through a wide straw.

Assemble & Garnish

Pour the shake into the prepared chilled glass, leaving about 1 inch (2.5 cm) of space at the top for whipped cream.

Top generously with 1 cup whipped cream, forming a soft peak.

Sprinkle 2 tablespoons crushed candy canes evenly over the whipped cream, then scatter 2 tablespoons mini marshmallows and 1 teaspoon red sanding sugar for sparkle.

Garnish with 4 fresh mint leaves and optionally rest a shortbread or sugar cookie on the rim or alongside the glass.

Serve immediately with a wide straw and long spoon so guests can enjoy crushed candy cane bits and marshmallows. If making ahead, do not add whipped cream or candy garnishes until ready to serve.