Prepare the Baking Sheet. Start by lining a baking sheet with parchment paper or a silicone mat.

Combine Ingredients. In a heavy-bottomed skillet, mix together the sugar, butter, water, and optional ground cinnamon. Heat over medium, stirring occasionally until glossy and bubbly.

Add the Walnuts. Once the toffee base is ready, add the walnut halves and stir constantly for 5–7 minutes until golden brown.

Infuse Flavor. Remove the skillet from heat and quickly stir in the vanilla extract and a pinch of sea salt.

Spread and Cool. Spread the coated walnuts in a single layer on the prepared baking sheet and cool completely for 10-15 minutes.

Break Apart and Store. Once cooled, break them apart if necessary and store in an airtight container.