In a mixing bowl, combine onion powder, garlic powder, lemon pepper, and salt. Season both sides of the breasts with some of this mixture. Set remaining seasoning aside for a later step.
Pour half of the skillet contents over the chicken in the crockpot. Layer on onions, lemon zest, and lemon slices. Pour remaining skillet contents over the lemons.
1/2 cup sliced onion, 1 Tablespoon lemon zest, 1 large lemon
Cook on high for 3-4 hours (or on low for 6-7 hours).
Remove lid and add capers. Replace lid and turn off the crockpot. Let sit 5 minutes to warm capers.
While many of our chicken recipes call for pounding the breasts to an even thickness, that is not necessary for this recipe. The thickness of the breast does not play a part because of the long cooking time.
You will need zest and lemon juice as well as a full lemon for slicing. While you can certainly zest the lemon you are going to slice, you will still need juice. So it’s best to have 2 or 3 lemons. You can realistically use bottled lemon juice, but I would highly, highly recommend using fresh. Especially for a recipe built around lemons!
If capers aren’t your thing, you can substitute with finely chopped green olives, or simply leave them out all together.