Quick and easy frittata

I love love love eggs and am thinking a frittata is a really quick lunch or dinner...The cool thing is you can mix up the ingredients to suit your taste or what is in the fridge.  Here is a recipe I found on taste and would like to try

Serves 2
30g unsalted butter
200g button mushrooms, thickly sliced
2 vine-ripened tomatoes, cut into wedges
4 eggs
75g mature cheddar, coarsely grated
1/2 cup parsley

Preheat the grill to high.

Melt 20g of the butter in a non-stick frypan over medium heat. Add the sliced mushrooms and tomato wedges, and cook, stirring, for 3-4 minutes until tomato is just softened.

Lightly beat eggs with 1 tablespoon water in a large bowl. Stir in cheese, parsley, and the mushroom and tomato mixture. Season with salt and pepper.

Melt remaining butter in the frypan over medium-low heat. Add the egg mixture, stir briefly, then cook for 5-6 minutes until golden underneath and nearly set. Place pan under hot grill for 3-4 minutes or until just set and top is golden. Slide onto a board, cut in half.