For the Country-style omelet
For each omelet, beat 3 eggs well and season with salt. Pour them over the ingredients in the skillet and stir gently. Heat a nonstick omelet pan over high heat and add the butter, tilting the pan to coat the entire surface. Poor the egg mixture into the pan and scramble it with the back of a fork, heatproof rubber spatula, or wooden spoon. Move the pan and utensil at the same time until the egg mixture has coagulated slightly. Smooth the eggs into an even layer. Reduce the heat to low and spread 1/3 of the bacon, tomatoes, feta and potatoes. Tilt the pan and slide a fork or spoon around the lip of the pan under the omelet; to be sure it is not sticking. Flip the omelet and let it cook until there is no more liquid egg visible. Alternatively you may place in a hot oven for a few minutes.