Preheat the oven to 370°F (175°C) and set an oven rack in the middle position. Lightly grease an 8 x 4–inch (20 x 10–cm) loaf pan with butter or nonstick cooking spray. Dust with flour, shaking off any excess.

To make the cake, mix the flours, xanthan gum, poppy seeds, light brown sugar, baking powder, baking soda and salt in a medium bowl.

In a separate bowl, mix the orange juice, oat milk, oil, citrus zest and vanilla well to combine. Pour the liquid mixture into the flour mixture and mix using a spatula or wooden spoon.

Pour the batter into the prepared loaf pan and bake for 30 to 35 minutes, until golden brown on top and a toothpick inserted in the middle comes out clean. Let the cake cool for 5 minutes in the pan, then transfer to a wire rack and let it cool completely before adding the cream cheese icing.

To make the icing, add the butter to a bowl. Give it a good mix using a wooden spatula until it becomes creamy. Add the vegan cream cheese and confectioners' sugar and mix vigorously, until the sugar is dissolved and the icing becomes smooth.

In a separate cup, smash the fresh raspberries and mix them with the lemon juice and half of the orange zest, keeping the other half for decorating the cake. Strain the raspberry mixture through a fine sieve then mix the puree with the vegan cream cheese mixture. Add the cold milk to make the icing more liquid, if needed.

Pour the icing over the completely cooled loaf cake and decorate with the reserved orange zest. Slice immediately, or refrigerate for 15 to 20 minutes to allow the icing to harden.