Cook Mushrooms:

Cup of Yum
1. Prepare mushrooms by tearing into small pieces. (Alternatively, slice them.) If using mushrooms with a tough stem (like shiitake or king oyster), discard and compost the stem.
2. Heat an omelette pan over medium heat. Add 1 TB butter and the oil. The butter will begin to foam as it melts. When it stops foaming, add the mushrooms in a single layer. Don't crowd the mushrooms or they will steam instead of browning. If you have too many mushrooms to fit in a single layer, work in batches.Tip: If your omelette pan is small, you may want to use a different pan to cook the mushrooms more quickly.
3. Toss the mushrooms frequently to make sure they cook evenly.When the mushrooms are lightly toasted, add half the chives (or other herbs) and garlic. Toss and cook for about another minute, until the garlic is fragrant.Remove the mushrooms from the pan. Wipe the pan out and let it cool down slightly while you prepare the eggs.Mushrooms can be prepared up to a day ahead of time. Refrigerate until ready to use, and rewarm before adding to the omelette.

Make the Omelette:

1. Whisk eggs together the eggs and milk.Return the omelette pan to just under medium heat.  Add remaining butter, and let it melt.  (Do not let the butter brown.)Pour eggs into pan, swirl eggs around pan to spread out the mixture, and then add salt and remaining herbs to the center of the mixture. DON'T TOUCH your omelette for about 2 minutes. 
2. Add the cheese and about ⅔ of the cooked mushrooms.Once the edges of the eggs start pulling away from the pan and appear crisp, use a plastic spatula to fold (or roll) the omelette together.Remove from heat immediately, even though the inside will still appear runny, because the inside will continue cooking from the heat of the surrounding egg.Top with remaining mushrooms (and more herbs if desired) and serve immediately.