In large pot over medium heat, heat oil.

Drop in three popcorn kernels and wait until they all pop. (Note: This ensures that oil is at correct heat level.)

Remove pot from heat, add remaining popcorn and shake to evenly spread kernels.

Return pot to heat and cover with lid, shaking frequently.

Once popcorn starts popping, shake pot gently to ensure all kernels receive heat.

When popping slows and almost stops, remove pot from heat and transfer popcorn to large bowl.

Preheat oven to 225 degrees F. Line two baking trays with parchment paper.

In saucepan over medium heat, melt butter.

Add corn syrup, sugar and salt. Stir until just barely combined.

Once mixture begins to bubble, let simmer 4 minutes without stirring.

Remove from heat and whisk in vanilla and baking soda. (Note: The caramel will start to foam and expand.)

Drizzle caramel mixture over popcorn and toss to ensure even coat.

On baking trays, spread out coated popcorn.

Bake 45 minutes, stopping every 10 minutes to shake and toss as caramel re-melts.

After 45 minutes, remove popcorn from oven and let cool.

Break apart pieces and serve or store in airtight container for up to two weeks.