1Combine sugar, butter, syrup, and salt. Cook on low heat until it boils. Boil for 5 minutes and take off heat.
2Add vanilla, baking soda, pinch of cream of tartar. Pour over popped popcorn in a sheet pan and stir until most of the popped corn is covered.
3Bake for one hour on 250F in oven and stir every 15 minutes.
4Cool, break into chunks.