Almond Thumbprint Cookies with Dark Chocolate and Sea Salt

INGREDIENTS

• 4 oz bittersweet chocolate, broken into small pieces
• 1 cup all-purpose flour
• 1 stick (4 ounces) unsalted butter, at room temperature + 2 tablespoons (for chocolate filling)
• ¾ cup almond meal
• sea salt, to taste
• 1 teaspoon pure vanilla extract
• 2 teaspoons golden syrup or light corn syrup
• ¼ cup granulated sugar
• finely grated zest from 1 small lemon