Make the crepes: In a blender, combine the egg, whole milk, flour, 1 1/2 tablespoons melted butter, the herbs, water, and salt, and pulse 10 seconds. Place the crepe batter in the refrigerator for 1 hour; this allows the bubbles to subside so the crepes will be less likely to tear during cooking. The batter will keep for up to 48 hours in the refrigerator.
Heat a 6-inch carbon steel skillet over medium-low heat. Add butter to coat, about 1/2 teaspoon. Pour 3 tablespoons batter into the center of the pan and swirl to spread evenly. Cook 10 to 20 seconds and flip. Cook 10 more seconds and remove to a cutting board. Repeat until all of the batter is gone, laying the crepes out flat so they can cool. After they have cooled, you can stack them and refrigerate in sealed plastic bags for several days or freeze for up to 2 months.
Make the quiches: Heat oven to 325ºF. In a small saute pan over medium heat, melt the butter and sweat the onion until translucent. In a small bowl, mix the cooked onion and crumbled bacon together. In a separate bowl, whisk the eggs with the milk and season with salt and pepper.
Generously grease a nonstick, 6-cup muffin tin, then place one crepe in each cup. Make sure the edges of the crepes are slightly pleated and overlap the edges of the cups slightly. Spoon the bacon and onion mixture into each cup. Distribute the cheese evenly among the cups. Pour the egg mixture into the cups so all the quiches are the same size. Transfer to the oven and bake until the egg mixture is completely set, 25 to 30 minutes. Let rest 5 minutes before serving.