Go the old fashioned route to make homemade whipped cream when you just need a small batch. I add just a smidge of sugar to sweeten it—about 1/2 teaspoon for a 1/2 cup of cream. Adjust as you like, or leave it out all together for an unsweetened version.
Add the cream, sugar, and marble to the mason jar. Cover with the lid, and screw on tightly. Shake vigorously until soft peaks form, 60 to 90 seconds for a billowy whipped cream, or closer to 2 minutes for a more structured whipped cream with stiff peaks.