Combine all-purpose flour, eggs, kefir, salt. Add baking soda combined with vinegar. Knead the dough and then pour it over the drizzled with oil baking sheet.
Top the dough with sliced tomatoes and onions. Sprinkle with cheese. Place into the preheated oven to 400°F (200°C). Bake about 20-30 minutes or until golden brown. Enjoy your meal!!!