Preheat the oven to the broil setting and position the rack in the upper third of the oven.
Preheat an ovenproof skillet over medium heat.
Cut the bacon crosswise into ¼-inch-thick strips.
6 slices bacon
Once the skillet is hot, add the bacon strips. Cook, stirring occasionally, until the bacon is crispy, 4 to 6 minutes. Once done, transfer to a plate lined with paper towels, leaving the drippings in the skillet.
While the bacon cooks, trim off and discard the ends of the shallots; peel and halve the shallots lengthwise, then thinly slice crosswise into half-rounds.
Once the bacon has been transferred, add the shallots to the skillet; cook, stirring frequently, until softened, 2 to 3 minutes.
While the shallots cooks, medium dice the potatoes (cut into ½-inch cubes).
Add the potatoes to the skillet; cook, stirring occasionally, until softened, 6 to 8 minutes.
While the potatoes cook, cut out and discard the kale stems; chop the leaves crosswise into 1-inch strips.
Add the kale to the skillet; cook, stirring, until it is wilted but still green, 4 to 5 minutes.
While the kale cooks, in a medium bowl, combine and whisk together the eggs, water, salt, and pepper.
4 tbsp water
½ tsp salt
¼ tsp black pepper
Pour the egg mixture into the skillet and top with the bacon. While tilting the skillet with one hand, lift up the edges of the frittata with a spatula and let the egg mixture run underneath during the first few minutes of cooking. Cook until most of the frittata is set, but the top is still runny, 4 to 5 minutes.
Transfer the skillet to the oven and broil until the top is set and lightly browned, 2 to 3 minutes.
To serve, separate the frittata into wedges and divide between plates. Enjoy!