Line a rimmed baking pan with parchment paper and set it nearby. Clip a candy thermometer to a heavy-bottomed saucepan so the tip will sit in the center of the pan.

Add 2 cups unsalted butter, 2 cups granulated sugar, and 1/4 teaspoon salt to the saucepan. Cook over medium heat, stirring and scraping the bottom and sides often, until the mixture melts, turns amber in color, and reaches 300°F (150°C) on the candy thermometer.

Remove the pan from heat immediately and pour the hot toffee evenly into the prepared parchment-lined pan. Use a heatproof spatula to spread it as evenly as you can.

Immediately sprinkle 2 cups mini semisweet chocolate chips evenly over the hot toffee. Let the chips sit undisturbed for a minute or two until they soften and begin to melt.

Use a spatula to smooth the melted chocolate into an even layer over the toffee.

Sprinkle 1 cup chopped almonds evenly over the melted chocolate and press the nuts gently with the back of a spatula so they adhere.

Refrigerate the pan until the toffee and chocolate are fully set. When set, lift the parchment to remove the toffee, break it into pieces, and serve.