Begin by cooking your bacon in an uncoated pan over medium heat until it's crispy. Remove from the pan and set aside on a paper towel to blot up excess grease.
Prep your vegetables while the bacon is cooking. Leeks tend to hold onto dirt and grit, so it's important to wash them well. Since the leeks are being chopped, the easiest way to wash them is to start by cutting off the leafy top. Leave the end with the roots intact. Then cut them lengthwise, starting about an inch above the root end. After you've made your first cut, give the leek a quarter turn and cut it in half again, so that it's now cut into 4ths but still held together at the end with the roots, Now you can fan them out under running water and wash off the dirt. Once they're clean, just chop them up and discard the root end.
For the kale, cut the stem out and then cut each leaf into ribbons lengthwise.
After removing the bacon from the pan, reserve about 2 Tbsp of bacon grease and then add the leeks and kale to the pan. Cook over medium heat until they begin to soften for about 3 minutes.
Turn the heat up to high and brown the liver for 2 minutes on each side for a total of 4 minutes.
While the liver is cooking, prep what will be your light gravy. In a small bowl whisk together chicken broth, flour or arrowroot flour, and garlic.
Add the chicken broth mixture to the pan once the liver has browned. You'll notice that it will immediately start sizzling. While it is sizzling, run a wooden spoon along the bottom of the pan. This will pull up drippings and add flavor to your dish. Continue to cook until the sizzling stops and the dish is simmering. At this point, remove the pan from the heat and serve immediately.