Preheat oven to 350°F.
Spread raw almonds on a large baking sheet so that they are just one layer. Roast the almonds for 15 minutes.
Meanwhile, in a large saucepan, bring butter, brown sugar and Karo to a boil for 5 minutes stirring constantly. Stir in vanilla, salt and baking soda. (This will cause the mixture to bubble up.)
Once the almonds are roasted, carefully pour them into the butter mixture. Stir until well coated.
Reduce oven heat to 250°F.
Cover a large baking sheet with foil. Using a slotted spoon, remove the coated almonds from the saucepan and place in a single layer on the baking sheet. (Don't touch the coated almonds with your fingers... the mixture makes the almonds very hot!)
Place in the oven for 15 minutes. Stir, then do another 15 minutes.
Remove the almonds from the oven. Using a spatula, place almonds on a piece of waxed paper until cool. Sprinkle with sea salt.
Store in an airtight container until ready to eat.
Enjoy!