Stir psyllium into the lukewarm water and leave 30–45 seconds to gel. Combine tapioca, millet, sorghum, sugar, instant yeast, baking powder, xanthan and salt in the mixer bowl.

Mix milk, egg and oil into the gel, then add to the dry ingredients. Knead until even, then continue 4–5 minutes with a dough hook, or 6–8 minutes by hand, scraping the bowl as needed. The dough remains soft and sticky; do not turn it into a stiff dough with extra flour. If necessary, refrigerate it for 1 hour to make handling easier.

On a well-floured surface with floured hands, divide into six portions of about 90 g. Round each, then flatten to approximately 4 inches wide and 1/2 inch thick. Space generously on a lined tray. Cover lightly and proof in a warm place for 60–75 minutes, until noticeably puffy.

While the buns proof, stir the cream cheese, filling sugar and vanilla smooth, then mix in its egg. Toss the strawberries with jam in another bowl. For streusel, combine its flour, brown sugar, xanthan and salt, then rub in the cold butter to make clumps.

Begin heating a conventional oven to 375°F / 190°C about 20 minutes before proofing finishes. Brush the buns with beaten egg, then press a deep central well roughly 2 3/4 inches wide into each. Add about 2 tbsp cheesecake filling per bun, top with strawberries and scatter streusel mainly over the rim.

Bake 18–20 minutes, until the bread is deeply golden and the filling is baked. Cool on the tray before serving warm or at room temperature. If strawberry topping remains, cook it separately in a saucepan for 2–3 minutes until the berries soften, then spoon onto the baked buns.