In a large bowl, combine the warm milk, sugar, and dry yeast. Stir gently and let it sit for about 5-10 minutes until it becomes frothy, indicating that the yeast is active.

To the yeast mixture, add half of the wheat flour along with the salt and poppy seeds. Mix until combined.

In a small bowl, beat the egg with the vegetable oil. Add this mixture to the dough.

Mix the baking soda with the vinegar in a small dish (it will fizz), and add it to the dough as well.

Gradually add the remaining flour to the mixture, kneading continuously. Knead until the dough is smooth and elastic, about 8-10 minutes. If the dough is too sticky, add a little more flour.

Place the dough in a greased bowl, cover it with a clean cloth, and let it rise in a warm, draft-free area for about 1 hour, or until it doubles in size.

After the first rise, knead the soft butter into the dough until fully incorporated.

Cover the dough again and let it rise for another 30-45 minutes.

Once the dough has risen, punch it down gently and shape it into a loaf. Place the loaf in a greased baking pan or on a baking sheet lined with parchment paper.

Preheat your oven to 180°C (350°F).

Place the dough in the preheated oven and bake for about 30-35 minutes, or until the bread is golden brown and sounds hollow when tapped.

Remove the bread from the oven and let it cool on a wire rack before slicing.