2 cups slivered almonds
3/4 cup heavy cream
4 tablespoons unsalted butter, cut into 4 pieces
1/2 cup (3 1/2 ounces) sugar
1/4 cup orange marmalade
3 tablespoons all-purpose flour
1 teaspoon vanilla extract
1/4 teaspoon grated orange zest
1/4 teaspoon salt
4 ounces bittersweet chocolate, chopped fine
1. Adjust oven racks to upper-middle and lower-middle positions and heat oven to 350 degrees. Line 2 baking sheets with parchment paper. Process almonds in food processor until they resemble coarse sand, about 30 seconds.
2. Bring cream, butter, and sugar to boil in medium saucepan over medium-high heat. Cook, stirring frequently, until mixture begins to thicken, 5 to 6 minutes. Continue to cook, stirring constantly, until mixture begins to brown at edges and is thick enough to leave trail that doesn’t immediately fill in when spatula is scraped along pan bottom, 1 to 2 minutes longer (it’s OK if some darker speckles appear in mixture). Remove pan from heat and stir in almonds, marmalade, flour, vanilla, orange zest, and salt until combined.
3. Drop 6 level tablespoons dough at least 3½ inches apart on each prepared sheet. When cool enough to handle, use damp fingers to press each portion into 2 1/2-inch circle.
4. Bake until deep brown from edge to edge, 15 to 17 minutes, switching and rotating sheets halfway through baking. Transfer cookies, still on parchment, to wire racks and let cool. Let baking sheets cool for 10 minutes, line with fresh parchment, and repeat portioning and baking remaining dough.
5. Microwave 3 ounces chocolate in bowl at 50 percent power, stirring frequently, until about two-thirds melted, 1 to 2 minutes. Remove bowl from microwave, add remaining 1 ounce chocolate, and stir until melted, returning to microwave for no more than 5 seconds at a time to complete melting if necessary. Transfer chocolate to small zipper-lock bag and snip off corner, making hole no larger than 1/16 inch.
6. Transfer cooled cookies directly to wire racks. Pipe zigzag of chocolate over each cookie, distributing chocolate evenly among all cookies. Refrigerate until chocolate is set, about 30 minutes, before serving. (Cookies can be stored at cool room temperature for up to 4 days.)