Pour cream into Churncraft jar. Close jar and churn cream vigorously; after several minutes of churning, whipped cream will fill entire jar. Continue churning. Whipped cream will slowly transition into butter and small clumps of yellow butter will start to appear. (If without a Churncraft butter churn, this can be replicated in a food processor or mason jar, the latter requiring you to shake the jar to produce butter.)
Once there are two distinct substances in the jar – thin, white buttermilk and thick clumps of yellow butter – strain remaining buttermilk into a separate container and reserve. Rinse butter in cold water and squeeze out residual buttermilk using spatula or clean hands. Rinse several times, until water runs clear.
Thoroughly stir the cinnamon and sugar into the homemade butter. Once mixed, add in the crushed pecans. Be sure to mix well.
Pack the butter into a ramekin or shape into a log using plastic wrap. Let it chill in refrigerator for ~30 minutes.