For the cupcakes: Preheat the oven to 325 degrees F. Prepare 2 cupcake pans with paper liners.
Puree the spinach to measure 1 cup. Sift together the flour, baking powder and salt into a bowl. Blend the sugar and eggs until creamy in the bowl of a stand mixer fitted with the paddle attachment, add then add the oil, lemon juice, vanilla and spinach puree and blend to combine. Slowly add the dry ingredients and mix for 30 more seconds.
Bake for 14 minutes, then let cool completely.
For the tomato marmalade: Bring a pot of water to a boil. Add the tomatoes and boil until the skin starts coming off, about 2 minutes, then plunge into a cold water bath. Peel, seed and dice the tomatoes. Transfer to a saucepan with the sugar, salt, cloves and cinnamon and cook until tender and syrupy, then let cool.
For the buttercream frosting: Beat the cream cheese in the bowl of a stand mixer using the paddle attachment until soft. Add the white chocolate and blend to combine, then mix in the butter, lemon juice and salt.
For assembly: Use a melon baller to remove the center of each cupcake and fill with tomato marmalade. Pipe the tops with the buttercream frosting and garnish with more tomato marmalade.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.