Preheat the oven to 350°F. Grease and flour a 10-cup bundt pan.

In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

Using a stand mixer, hand mixer, or whisk, whip the sugar, eggs, and orange zest in a large bowl on medium speed until pale, light, and fluffy, 7-10 minutes. Add the orange juice and olive oil and blend until combined.

Gently fold the flour mixture into the egg mixture until just combined. Using the bowl you just had the flour in, separate ⅓ of the cake batter. Fold the raspberry jam and food coloring, if using, into the smaller bowl of batter.

Pour a layer of the plain batter into the prepared pan. Add a ring of the raspberry batter, then add another layer of the plain batter. Repeat until all of the batter has been used. Using a long, thin skewer or knife, gently swirl the batter in circles around the pan to create a marbled effect. Don’t overdo this step or the marble effect will be too blended.

Bake the cake until a toothpick inserted into the center comes out clean, 35-40 minutes. Cool on a wire rack for 5 minutes before removing from the pan to cool completely.

To make the icing, combine 2 tablespoons of the orange juice, vanilla, and powdered sugar until smooth. If the icing is too stiff, add more juice until it becomes a thick but pourable consistency. Pour around the top of the cake, allowing the icing to drip off the sides. Decorate the cake with fresh raspberries, and let the icing set for at least 10 minutes before serving.

Note: If you are using a natural food coloring, you will need to use the full amount, as the color fades significantly during baking. If you are using artificial color, 4-6 drops should suffice.