- 1 tbs. soy protein isolate (has to be 85% protein by weight)
- 1 tbs. cornstarch
- ¼ tsp. cream of tartar
- ¼ cup water
- 1 tsp. vanilla extract
- 6 tbs. organic sugar
- ⅛ tsp. sea salt
- 1 stick (½ cup) vegan butter, cut into ½” pieces and softened
- Whisk protein powder, cornstarch, cream of tartar, and water until completely smooth. Pour into a small saucepan and add in vanilla, sugar, and salt. Bring to a rolling boil over low heat, scrapping the bottom and down the sides often, and immediately pour into a mixing bowl.
- Whip, starting on medium-low and slowly increasing to high speed, until stiff peaks almost form (be patient, this might take a while!). 3. Reduce to medium-low speed, and add in the butter a piece at a time.
- Increase to medium-high and continue to whip. Buttercream will break and become grainy, but be patient – it will recombine eventually!
- Beat until smooth, fluffy, and stiff, and refrigerate for 10-20 minutes before using. .
- If you want to make this in advance, feel free to do so! Refrigerate (up to 1-2 weeks) or freeze, and then rewhip until smooth and fluffy!