01 -
Line a 6- or 8-quart slow cooker with a large piece of foil extending up the sides and spray with nonstick cooking spray.
02 -
In a large bowl, whisk together milk, eggs, granulated sugar, one packet each of au jus gravy mix and ranch seasoning mix, and panko breadcrumbs until fully combined.
03 -
Add ground beef to the mixture and combine gently with clean hands, taking care not to overmix to avoid toughness.
04 -
Transfer the mixture to the slow cooker and shape it into an oval loaf.
05 -
In a separate bowl, whisk cold water, peperoncini juice, and the remaining packets of au jus gravy and ranch seasoning mix until well combined.
06 -
Pour the prepared gravy evenly over and around the meatloaf, then arrange peperoncini peppers on top.
07 -
Cook on low for 5 to 6 hours or on high for 3 to 4 hours, until internal temperature reaches 165°F (74°C).
08 -
Carefully lift the meatloaf from the slow cooker using two spatulas and place on a serving dish.
09 -
Strain cooking juices into a medium saucepan and heat over medium. Whisk cornstarch and water to create a slurry, then gradually whisk into simmering gravy. Cook for 1 minute until thickened, then remove from heat.
10 -
Slice the meatloaf and spoon the thickened gravy over each serving.