Prepare cookie sheets or foil by buttering them. Ensure the surface underneath is heat resistant.

Combine sugar, white Karo syrup, and water in a large pot.

Cook the mixture over medium heat, stirring occasionally, until it reaches 268°F (soft crack stage).

Add the raw peanuts to the pot, stirring constantly.

Continue cooking and stirring until the mixture turns golden brown and reaches 300°F (hard crack stage).

Remove the pot from the heat.

Quickly add butter, salt, and baking soda to the pot.

Blend all the ingredients thoroughly until well combined.

Immediately pour the hot peanut brittle mixture onto the prepared buttered foil or cookie sheets.

Spread the brittle thinly and quickly using a spatula or heat-resistant tool, as it begins to cool and harden rapidly.

Allow the peanut brittle to cool completely.

Once cooled and hardened, break the brittle into pieces and serve.