Preheat your oven to 350°F (175°C) and place cupcake liners in a muffin tin.

In a large mixing bowl, cream together the softened butter, orange zest, allspice, cardamom, nutmeg, and vanilla seeds until fluffy.

Gradually add the sugar, mixing until pale and well combined. Incorporate eggs one at a time.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add to the wet mixture alternately with buttermilk until just combined.

Fill cupcake liners halfway with batter and bake for 18-20 minutes.

Allow cupcakes to cool before frosting.

In a saucepan, combine sugar and water, bringing to a boil until it reaches 245°F (118°C).

Whip egg whites with cream of tartar until stiff peaks form. Slowly pour in the syrup while beating until glossy and cool.

Gradually add butter and cocoa powder, mixing until smooth. Add vanilla and beat until fluffy.

In a saucepan, whisk together orange juice, egg yolks, and sugar over low heat until thick.

Remove from heat, whisk in butter until melted, and chill until set.

Frost cooled cupcakes with buttercream and drizzle with orange curd. Garnish with orange zest and chocolate sprinkles.