Heat a small skillet over medium-high heat. Add pancetta and cook, stirring occasionally, until golden brown. Drain on a paper towel. Discard fat drippings.

Wipe out the skillet, set over medium heat and add olive oil.

Add mushrooms and cook, stirring occasionally, until mushrooms are tender, 4 to 5 minutes. Season with salt and pepper. Stir the roasted garlic into the mushrooms and cook for an additional minute. Set aside.

Crack the eggs into a small bowl, add water and whisk to combine. Coat a small, heatproof nonstick skillet (I used an 8-inch one) with cooking spray and set over medium heat. Add the eggs.

Cook the eggs, without stirring or shaking the pan, until the bottom is cooked but there is still layer of raw egg on top. Season with kosher salt and freshly ground black pepper, and top with the mushroom mixture and pancetta.

Place the skillet under the broiler and cook until the top of the frittata is just starting to brown and is slightly puffed.

Remove frittata from the oven and slide it onto a plate (use a spatula if necessary). Serve immediately.