Preheat oven to 350°F. Butter two 8-inch round cake pans. Line bottom of each pan with parchment paper. Butter paper.

Spread 12 bread slices with 1 teaspoon softened butter each; spread remaining 12 with 2 teaspoon marmalade each.  Sandwich slices with butter and marmalade facing.  Trim crusts.  Cut each sandwich into quarters diagonally; arrange in prepared pans, stacking and overlapping as necessary to fit snugly.  In a small bowl stir together raisins, brown sugar, and cinnamon; sprinkle over top.

In a large bowl, whisk together the cream, condensed milk, and eggs.  Pour the mixture evenly over the bread.  Press bread down to absorb the cream mixture.  Bake for 45 minutes or until a knife inserted in the center comes out clean.  Let cool for 20 minutes in pans on a wire rack.

Meanwhile, in a small saucepan warm remaining marmalade over low heat.

Loosen the sides of the bread pudding from the pans. Invert one pan onto a platter; shake gently to loosen bottom.  Remove parchment.  Spread with half of the warm marmalade.  Invert the second pan onto a baking sheet or wire rack, then invert it again onto a rimless baking sheet so top faces up; gently slide it onto the first layer.  Top with the remaining marmalade. 

Best when served within 2 hours.  If desired, top with slices of blood orange and a dollop of whipped cream garnished with a sprig of fresh rosemary.