Line a 9 by 13-inch baking pan with parchment paper, leaving overhang on all four sides.

In a medium heavy-bottomed Dutch oven or saucepan, combine butter, brown sugar, and 1/4 cup cold water. Bring to a boil over medium heat, stirring occasionally with a heatproof spatula.

Once sugar mixture comes to a boil, attach a candy thermometer and heat to 300°F (hard crack stage). This will take approximately 10 to 12 minutes.

In a small bowl, combine chopped almonds and baking soda. Set this and the vanilla and salt nearby for quick use.

Once sugar mixture reaches 300°F, remove from heat. Carefully stir in almond mixture, vanilla, and salt. Pour onto the prepared baking pan, smooth into an even layer, and score into 12 pieces once slightly set. Cool in the fridge for 20 minutes.

Once toffee is cool, cut into portions along the score marks and set on a parchment-lined tray.

Melt white chocolate and oil over a double boiler until smooth and shiny.

Combine sugar and cinnamon in a bowl. Dip toffee pieces into the melted chocolate to coat all sides. Sprinkle with cinnamon sugar and set aside on a parchment-lined tray.