Knead CMC into orange fondant until pliable, then roll into strips for the witches’ legs. Cut these strips into pieces, and shape black fondant into shoes to attach to the orange legs using a damp brush for adhesion.

Preheat your oven to 340°F (170°C). Cream together the butter and sugar until fluffy, then whisk in the eggs. Combine and sift together the dry ingredients, then alternate adding them with milk while folding in vanilla. Bake in a greased square pan for 45-50 minutes, or until a skewer inserted comes out clean. Allow to cool completely.

In a mixing bowl, cream the unsalted butter until smooth. Gradually add in the powdered sugar until combined, then incorporate vanilla extract and green food coloring until you achieve the desired vibrant hue.

Cut the cooled cake into circles to fit inside your jars. Layer these cake pieces with buttercream and festive sprinkles. Top off with additional buttercream, then insert the fondant legs into the jars for charming decoration.