Mix all dry ingredients for the dough: wheat and cornflour, baking powder, sugar, salt. In another bowl, combine the liquid ingredients: milk, sour cream, egg, and vegetable oil. You can do this with a mixer. Gradually add the liquid part of the dough to the dry part and knead the dough. Do not knead for a long time, just so that everything grabs (the dough will be thick, like a pancake).
Grease a baking dish and place the dough in it. I did not line the glass form with paper, but the metal one should be covered with parchment.
We bake cornbread for 35 to 50 minutes. Depends on the chosen shape and oven. You can check readiness with a toothpick. Let the bread rest for 10-15 minutes.