Prepare a rimmed baking sheet by lining with parchment paper (I use a half sheet pan) and measure all your ingredients (esp. the baking soda) in advance.
Combine the sugar, corn syrup, water, vinegar and one pinch of salt in a large, nonreactive saucepan (it's best if the pan has a light interior, so you can see color) and give it a good stir to combine.
Heat over high heat without stirring until the mixture reaches hard ball stage (238 degrees F on a candy thermometer -- it will be pretty viscous and bubbling).
Add pecans and additional pinch of salt, stir to coat pecans and continue to cook until the mixture is a deep golden color (somewhere north of 310 degrees on a candy thermometer, but you really need to eyeball it).
Immediately dump in baking soda, stir to incorporate and pour out onto prepared baking sheet (the mixture will foam and expand a great deal and get all over whatever pot holders you're using, your spoon (I use a silicone spatula to stir) and probably your apron. Be careful because it's very hot, but fortunately sugar dissolves easily in water and cleanup is surprisingly not difficult). Allow the mixture to cool, then break into pieces and enjoy.
Notes
(Adapted from my awesome friend Carol)
Recipe by The Domestic Front at https://www.thedomesticfront.com/last-minute-gift-pecan-brittle/