In large, heavy-bottomed pot (with a lid), place oil and about 3 popcorn kernels. Heat over medium-high heat until a kernel pops. Add remaining popcorn; cover.
Once corn begins to pop, shake pot constantly over heat. When popping slows, remove pot from heat and transfer popcorn to a serving bowl.
Pour butter over popcorn, if desired, and toss.
Sprinkle yeast and curry powder, if desired, over popcorn and toss to distribute evenly.
Serve immediately or store in an airtight container.