Country-Style Omelette

I originally seen this recipe prepared on Ricardo and Friends on the Food Network. I used a stainless steel pan and I found the recipe took a little longer to bake. Almost 10 more minutes.
You'll know when it's done when the center puffs like the edges and just starting to lightly brown.

Country-Style Omelette

Ingredients
1/4 cup unbleached all-purpose flour
1 teaspoon baking powder
8 eggs, lightly beaten
1 1/2 cups milk
2 tablespoons rendered salt pork fat (see Crispy Pork Rinds) or bacon fat
1 pinch salt and pepper

Directions
1.With the rack in the middle position, preheat the oven to 180°C (350°F).
2.In a bowl, combine the flour and baking powder. Add the equivalent of 1 egg, whisking until the mixture is smooth. Add the remaining eggs and the milk. Season with salt and pepper. Set aside.
3.Pour the fat into a hot cast iron skillet and add the egg mixture. Stir to combine. Transfer to the oven and bake until the omelette is golden and slightly puffy, about 25 minutes. Serve immediately, as the omelette will start to collapse after about 3 minutes.