Cookies: Preheat oven to 350°F. In a medium bowl, whisk together flour, salt, baking soda, and spices. In a stand mixer bowl fitted with paddle attachment, beat butter with granulated sugar on medium-high speed until light and fluffy, about 2 minutes. Add egg; beat to combine. Add sour cream and molasses; beat to combine. Reduce speed to low; beat in flour mixture until fully combined.Advertisement
Divide dough into 2 different-sized pieces: one piece being two-thirds of the dough, the other being one-third. From larger piece, make "caps": Scoop level tablespoons of dough and roll into balls. Cup each in the palm of your hand and use a finger to make a deep indentation. Place indent-side down on a parchment-lined baking sheet, spaced 1 1/2 inches apart.
From smaller piece, make "stems": Scoop rounded teaspoons of dough; roll each into a cylinder that's slightly pointed at one end, like a teardrop. Place on parchment-lined baking sheet, spaced 1 inch apart. Refrigerate 20 minutes. Bake until firm, 10 to 12 minutes. (If necessary, use a chopstick or similar-size dowel to reshape indents in caps after baking, so you can insert pointed ends of stems.) Transfer on sheets to wire racks; let cool completely.
Chocolate Glaze: Combine chocolate, confectioners' sugar, cocoa, salt, and butter in a heat-proof bowl. Heat cream in a small pot over medium-high until bubbling around edges, 1 to 2 minutes. Pour hot cream over chocolate mixture; let stand 1 minute. Add vanilla; whisk until mixture is smooth and has the consistency of hot-fudge sauce. (If too thick, whisk in more cream, 1 tablespoon at a time.)
Vanilla Glaze: Whisk together egg white and confectioners' sugar until smooth. Whisk in vanilla; texture should be like thick honey. (If too thin, add more sugar; if too thick, add a tiny bit of water.)
Dip cooled caps in either chocolate or vanilla glaze. Place, glazed-sides up, on wire rack. Sprinkle with pistachios or raspberries. Dip wider ends of stems in vanilla glaze to come about halfway up stems; dip bottoms in poppy seeds. Place, rounded-sides up, on rack; let stand until completely set, about 1 hour for vanilla, 2 hours for chocolate.
Dip pointed ends of stems in vanilla glaze and insert into indents in caps. (If glaze has thickened too much, loosen with a little water.) Return to rack; let stand until completely set. Cookies can be stored in an airtight container at room temperature up to 3 days.