Whisk the gluten-free flour, sugar, baking powder, and salt together in a mixing bowl.

Stir together the oat milk and blond psyllium husk, then let it sit for 2 to 3 minutes. Add the instant yeast to the bowl of a stand mixer with the oat milk mixture, then add the eggs.

Add the flour mixture and softened butter to the wet ingredients, then mix with the paddle attachment on medium speed for about 3 minutes. Scrape down the bottom of the bowl well to make sure all the flour is incorporated.

If mixing by hand, use a wooden spoon to combine the ingredients, then knead gently until the dough is smooth and even. The dough will be sticky.

Transfer the dough to a bowl once it is smooth. Cover and refrigerate for at least 3 hours, or until doubled in size.

Deflate the dough, then fold in the dried cranberries. Dust with a little more flour if the dough is too sticky. Shape it to fit the loaf pan, then transfer it to the greased Pullman loaf pan.

Cover with a damp cloth or plastic wrap and let rise in a warm place for about 45 minutes, or until the dough has roughly doubled in volume.

Preheat the oven to 200 °C. Once the bread has risen, slide the lid onto the Pullman loaf pan and bake for 28 to 30 minutes.

Remove the lid and let the bread cool in the pan for 5 to 10 minutes before transferring it to a wire rack to cool completely.