Step 1: Prep Your Baking Sheet - Line a baking sheet with parchment paper to prevent sticking.
Step 2: Combine Ingredients - In a heavy-bottomed saucepan, combine the sugar or erythritol, plant-based butter, water, and salt. Add vanilla extract if using. Stir gently.
Step 3: Heat the Mixture - Place the saucepan over medium heat, stirring continuously until the butter melts and sugar dissolves. Stop stirring and let it come to a boil.
Step 4: Cook to the Right Temperature - Cook until the mixture reaches 300°F (hard crack stage). Test by dropping a small amount into cold water.
Step 5: Pour and Spread - Once at the desired temperature, pour onto the prepared baking sheet and spread evenly with a spatula.
Step 6: Add Toppings - Sprinkle chocolate chips on top of the hot toffee. Let sit to melt, then spread. Top with walnuts or pretzels.
Step 7: Cool and Break - Allow to cool completely at room temperature, then break into pieces and enjoy!