Line a baking sheet with parchment paper.
Heat the butter, sugar, water, pumpkin puree, pumpkin spice and salt over medium heat in a saucepan fitted with a candy thermometer. Cook, stirring occasionally, until the mixture reaches 298 degrees F, about 10 minutes. Remove from the heat and stir in the vanilla extract.
Immediately pour the mixture on the parchment paper and spread it out in an even thin layer. Let it cool completely.
Melt the chocolate and coconut oil in the microwave. I like to do this in 30 second increments, stirring after each time. Once melted, pour the mixture over the set toffee layer.
Sprinkle with the pepitas, pecans and chocolate chunks. You can add some flaked sea salt or a sprinkle of pumpkin spice if you wish as well! Let the chocolate layer set completely.
Break into pieces and serve!