Preheat oven to 350°F. Spray three donut pans with nonstick spray. (See note if you don't have three pans)
Combine flour, baking soda, salt, and 3 Tbsp. chai spice mixture in small bowl. Set aside.
Combine Greek yogurt, heavy cream, and vanilla in small bowl. Set aside.
Add butter, sugar, and molasses to standing mixture. Combine for 2 minutes on high speed.
Add egg. Run mixer for one minute. Add second egg. Let mixture run for one minute.
Reduce speed to low. Add flour mixture. Mix until combined.
Add yogurt mixture. Mix until combined.
Scrape down sides and transfer batter to piping bag fitted with round piping tip. Pipe into prepared donut pans and bake for 10-15 minutes or until donuts bounce back slightly.
Remove pans from oven and let cool on cooling rack for 5 minutes. Remove donuts from pans and let cool completely.