Emily Rudnick remembers vividly the first time she and her dad mixed up a batch of the sneakily hot spice that bears her family name. She and her dad stopped by the Savory Spice Shop in Denver and picked up the 15 ingredients — including five different chilies — that make up Rudspice, a dry concoction she started developing in 2014 after experimenting with barbecue dry rubs. “We took them home and we mixed them up in our Kitchenaid and it did not go well,” the 14-year-old said.