- 8 Tbsp (4 oz) butter, divided
- 1 (12-oz) package sugar-free erythritol sweetener (we used Swerve brand)
- 2 tsp pure vanilla extract
- 3/4 cup roasted, salted almonds, roughly chopped
- 3/4 cup roasted, salted cashews, roughly chopped
- 1/4 cup roasted, salted pepitas
- 1/4 cup black sesame seeds, white sesame seeds, or a combination
- Line a large (18 by 13-inch) rimmed baking sheet with a silicone mat or parchment paper. Grease the mat or parchment and the head of a silicone spatula with 1 tablespoon of the butter. Set aside.
- Combine the remaining 7 tablespoons butter, sweetener, and vanilla in a medium, heavy-bottomed, stainless steel saucepan. Heat over medium heat, stirring constantly, until the sweetener is fully dissolved, 6 to 8 minutes. Continue cooking, stirring constantly, just until the mixture reaches a deep brown/amber color then quickly remove the pan from the heat to avoid burning, 7 to 8 minutes.
- Use the buttered spatula to quickly mix in the nuts and seeds, then pour the mixture onto the prepared baking pan. Smooth out the nuts so they are evenly distributed, making sure the brittle mixture is touching all the nuts and seeds. Refrigerate to set, 1 hour.
- Break the brittle into pieces and serve.