In large bowl, whisk flour, baking powder, salt and baking soda until well combined. In medium bowl, whisk sour cream, milk, olive oil and sugar until smooth.

Add half of wet ingredients to dry ingredients and stir with spatula. Add remaining wet ingredients and stir until mixture starts to come together.

Dump dough onto clean, floured work surface. Knead dough for AT LEAST 4 minutes or until smooth. If dough begins to stick to work surface at any point, sprinkle surface with a little more flour.

Leave dough on work surface to rest 10 minutes. Then, divide dough into 4 even pieces and use flour work surface and floured rolling pin to roll each piece of dough 1/4-inch thick at most.

Preheat oven to 350 degrees F. Heat large cast iron skillet over medium heat; add 1 tablespoon vegetable oil. Transfer 1 rolled dough piece to skillet and cook 2 to 3 minutes or until golden brown, flipping once. Repeat process with remaining dough pieces and vegetable oil.

Place flatbreads on rimmed baking pans and top with goat cheese (smear it onto flatbread a little), tomatoes and chives. Transfer to oven for 8 to 10 minutes to finish cooking. Cut and serve immediately.