Preheat oven to 350˚F. Spray a 12-cup Bunt or tube pan with baking spray and set aside.

Whisk together the flour, baking powder, and salt in a large bowl and set aside.

In the bowl of a stand mixer fitted with a paddle attachment (or with a handheld mixer in a large bowl) beat the eggs on medium-high speed until well-combined, about 1 minute. Slowly pour in the granulated sugar and continue beating until thick and pale yellow, about 3 minutes.

On low speed, alternate adding the flour mixture and oil, starting and ending with the flour, and beat until just a few wisps of flour remain. Pour in the clementtine juice and zest and mix for about 20 seconds to bring the batter together.

Pour the batter into the prepared pan and bake until a cake tester comes out with a few moist crumbs clinging to it, about 1 ¼ hours. If the top is browning too much as the cake bakes, cover lightly with foil.

Transfer to a wire rack and cool for 15 minutes, then turn the cake out onto the rack and cool completely before icing

For the drizzle, place marmalade in microwave for 30 seconds or heat in a small pan over low heat till melted. Strain warm marmalade through a fine strainer, push on solids with the back of a spoon. You should end up with approximately 3 tablespoons of strained marmalade.

Combine marmalade, 4 tablespoon of half and half, vanilla and powdered sugar in a medium size bowl. Mix with a wire whisk until smooth. Add more half and half or milk if needed to thin enough to drizzle. With a spoon drizzle icing in a back and forth motion from center to outer edges of cake.

Allow icing to set before serving. Cake is even better if made a day in advance. Store in a covered cake container.