This recipe, adapted from John Scharffenberger and Robert Steinberg's book, The Essence of Chocolate, is not to be missed. Almond Roca is confection that is buttercrunch toffee covered with chocolate and almonds. It is great for snacks, and makes a perfect holiday treat; break the roca into big irregular pieces and pack them into festive gift tins, or store in your freezer. Even frozen, the roca is pretty hard to resist.
CANDY RECIPE HELP

INGREDIENTS

1 pound unsalted butter, cut into chunks, plus more for the pan

3 cups granulated sugar

1/4 cup plus

2 tablespoons water

1/2 teaspoon freshly squeezed lemon juice

2 tablespoons light corn syrup

3 1/2 cups coarsely chopped toasted slivered almonds

9 ounces semi-sweet or milk chocolate, melted
1/2 teaspoon sea salt, or more, if desired

INSTRUCTIONS
1. Lightly butter a 17- x -12- x 1-inch baking sheet (half sheet pan), and line with parchment paper to cover the bottom and all sides.  

2. Melt the butter in a large deep heavy-bottomed pan over medium-high heat. Add the sugar to the middle of the pot.

Then add in the water around the sides of the sugar, and lemon juice, and corn syrup right on top of the sugar.
SARAH SAYS: You want to avoid splashing excess sugar on the sides of the pot.

3. Bring the mixture to a gentle boil, stirring to dissolve the sugar. Once the mixture boils, STOP stirring.
Brush down any sugar crystals clinging to the sides of the pan with a clean pastry brush dipped in water. 
SARAH SAYS: Dip the brush in water every time before washing the side of the pan! This step removes crystals that may have accumulated on the inside of the pan. If allowed to remain, these crystals might cause the sugar mixture to crystallize or the resulting candy to become grainy.

4. Clip a candy thermometer to the side of the pan and cook for 15 minutes, or until the mixture reaches 300 degrees F (150 degrees C). 

If the mixture threatens to boil over, lower the heat as necessary. (If the liquid is too shallow for the thermometer to measure the temperature, tilt the pot to get an accurate reading.) Do NOT stir; if the caramel is not coloring evenly, rather swirl the pan from time to time.

5. Remove the pan from the heat and stir in 2 cups of the almonds. Quickly spread the caramel in an even layer on the prepared baking sheet. Let cool completely.

6. Spread the chocolate over the top of the caramel, then sprinkle with the remaining 1 1/2 cups almonds and sprinkle with sea salt. Let the chocolate harden at room temperature or in the refrigerator.

7. Break the roca into irregular pieces.

STORAGE
Store in an airtight container at room temperature or freeze for longer storage.