Measure out the base ingredients: milk, vanilla ice cream, and heavy cream (if using). Let ice cream sit 2–3 minutes at room temperature if it’s extremely hard so it blends smoothly.

Making the Shake

Add milk, vanilla ice cream, heavy cream, granulated sugar, and vanilla extract to a blender. This is the neutral base; adjust milk quantity later to reach desired thickness.

Choose your flavor add-ins from the Add-ins section. For example: • Chocolate: add chocolate syrup. • Strawberry: add hulled strawberries. • Banana: add sliced banana. • Peanut butter: add peanut butter. • Coffee: add cooled coffee. • Cookies/candy: add crushed cookies or candy pieces.

If using ice to thin the shake slightly or quickly chill, add 3–4 ice cubes to the blender. (Skip if you want the thick, traditional custard-like shake.)

Blend on medium-high for 20–40 seconds, stopping to scrape down the sides once. Blend until smooth but still thick. If the shake is too thick, add milk 1 tablespoon at a time and pulse until you reach desired consistency; if too thin, add 1/4 cup more ice cream and blend briefly.

Taste and adjust sweetness or flavor: add an extra 1 teaspoon sugar or 1 tablespoon chocolate syrup/peanut butter/coffee as needed and pulse to combine.

Serving

Remove chilled glass from freezer (if used). Pour the shake into the glass, using a spatula to get all the thicker bits from the blender.

Top with whipped cream, sprinkle with chocolate shavings or sprinkles, and finish with a maraschino cherry if desired.

Serve immediately with a wide straw or spoon. Leftover shake can be refrigerated for up to 24 hours but will thin and separate; re-blend briefly before serving.