Grease a 9x13 baking dish and set aside.

In a small saucepan, pour in 2 cups of sugar and cook over low heat while stirring often until sugar is completely melted, about 20 minutes.

In a large saucepan, add the remaining 4 cups of sugar and heavy cream. Simmer over low heat until the sugar in your small saucepan has melted. Add melted sugar to the large saucepan while continuously stirring.

Increase heat to medium and cook mixture until it reaches 244 degrees F or the softball stage.

Remove from heat and stir in baking soda until completely combined.

Add butter and vanilla, stirring until the butter melts and mixture is smooth.

Let rest for 20 minutes.

Stir in nuts until the sheen has gone, then transfer to prepared baking dish.

Let cool for 1-2 hours or overnight. Cut into small squares to serve.