Prepare your cold brew coffee ahead of time and ensure it's completely chilled in the refrigerator. If using regular brewed coffee, brew it double strength and let it cool completely for at least 30 minutes in the fridge, as warm coffee will melt the ice cream too quickly.
Remove the vanilla ice cream from the freezer and let it sit at room temperature for about 2-3 minutes to soften slightly. The ice cream should be soft enough to scoop easily but not melted, which will help it blend more smoothly with the coffee.
Add the cold brew coffee to your blender first, followed by the softened vanilla ice cream. Pour in the milk and vanilla extract to help create that signature creamy texture.
If you prefer a sweeter drink like the original, add the granulated sugar at this point. Taste your ice cream first—if it's already very sweet, you may want to skip the extra sugar.
Blend on medium-high speed for 20-30 seconds until the mixture is completely smooth and creamy with no visible ice cream chunks. The consistency should be thick like a milkshake but still pourable, with a light tan color throughout.
Stop the blender and check the consistency by lifting the lid and observing how the mixture flows. If it's too thick and not blending well, add another tablespoon of milk and blend for 10 more seconds.
Pour the frosted coffee into a tall glass immediately while it's still cold and creamy. The drink should have a smooth, velvety texture that coats the back of a spoon.
Serve immediately with a straw and enjoy right away for the best texture and temperature. The frosted coffee is best consumed within 5 minutes before it begins to separate or melt too much.
