Clean the blender. Ensure your blender is clean and dry before starting.
Combine. Scoop vanilla or chocolate ice cream into the blender. Chocolate ice cream yields a richer chocolate flavor, while vanilla provides a milder base. Add cocoa powder to the blender to enhance the chocolate taste. Then, add in hot fudge sauce or chocolate syrup. For a more intense flavor, opt for hot fudge sauce. Pour in the heavy cream or whole milk; start with a smaller amount, and you can adjust the thickness later.
Blend. Secure the blender lid and blend on medium speed until the mixture is smooth and creamy. If the milkshake is too thick, add more cream or milk, a tablespoon at a time, blending after each addition until you reach the desired consistency.
Taste test. Taste the milkshake and adjust. If you prefer a sweeter flavor, add a bit more chocolate sauce and blend again.
Serve. Pour the milkshake into chilled glasses. Top with whipped cream, chocolate shavings, fresh strawberries, or an extra drizzle of chocolate sauce, as desired. Serve immediately with a straw or spoon and enjoy your homemade chocolate milkshake!