Cardamom Lemon Chocolate Marble Cupcakes

My daughter made these cupcakes for a weekday get together with friends. They came out just beautiful with swirls of chocolate. That was perfect, no need to top them for decoration which would take a bit longer.

Ingredients 
1 stick unsalted butter
1 cup granulated sugar
1/2 tsp salt
3 eggs
1 tsp vanilla
2 cups all-purpose flour
2 tsp baking powder
2/3 cup buttermilk
1/4 cup cocoa powder
Zest of one lemon
2 tsp ground cardamom

Note: If you don't have buttermilk, you can make a great replacement by mixing a tablespoon of white vinegar per 1/2 cup of milk and leaving it on the counter for 20 minutes.

Directions 

1. Preheat oven to 325 degF. Line a muffin pan with paper cupcake liners. 
2. Mix the flour, baking powder and salt in a bowl.
3. In another bowl, mix the cocoa powder with 2 tablespoons of hot water until it forms a smooth liquid paste.
4. Beat the butter and sugar together in a stand or hand mixer until smooth and airy.
5. Add the eggs one at a time, and the vanilla, and beat until the mixture is well combined.
6. Add the flour mix and the buttermilk little by little, each time beating the batter until it is smooth.
7. Put 1/2 of the batter in a separate bowl and add the cocoa to it. Mix well until well combined.
8. Add the lemon zest and the cardamom to the other 1/2 of the batter and combine.
9. Put one spoonful of the lemon/cardamom batter in the bottom of each mold and top it off with a spoon of the chocolate mixture.
   
10. Cook for 12 minutes for small cupcakes, and 16 minutes for muffin-sized ones.
11. Let cool fully in the pan before removing.