Preheat the oven to 350ºF
Bring a medium sauté pan to medium-high heat and add just enough Olive Oil to coat the bottom. Add the Onion and Celery and cook, constantly stirring, until wilted but not browned. Transfer the vegetables to a medium bowl to cool.
Using your hands only, break apart the three ground meats as you put them into a large bowl. Add 2 teaspoons of the Chives, 2 teaspoons of the Parsley, 1/2 teaspoon of the Thyme and the ground Panko to the meat without mixing.
When the Onions and Celery have cooled, add the Eggs, Half & Half, Kosher Salt and Freshly Ground Black Pepper and stir to combine. Mash 10 cloves of the Roasted Garlic and add to the Onion mixture.
Pour the Onion mixture over the ground meats and herbs. Use a rubber spatula to make sure you get all of the moistened ingredients out of the bowl and onto the meats. Using your hands, blend the ingredients just until well combined and everything is evenly distributed.
Line a large baking sheet with a silicone mat or parchment paper. Put the meat mixture on the mat or paper and compress it to make sure there are no pockets of air. Shape into a 2“ high and 5” wide loaf, keeping the sides straight instead of the typical mounded free form loaf.
Put the Meatloaf in the oven and bake until a thermometer reads an internal temperature of 155º, about 45 to 50 minutes. Remove the Meatloaf from the oven and let it rest for 10 minutes.
While the Meatloaf is baking, mash the remaining 10 cloves of Roasted Garlic. Bring the Beef Stock, mashed Garlic and the Unsalted Butter to a boil for 2 minutes in a small sauce pan over medium-high heat. Reduce the heat and simmer for 30 minutes, or until slightly thickened.
Add 1 teaspoon each of the Chives and Parsley and 1/2 teaspoon of the Thyme. Stir until blended, cover and remove from heat and let steep for 10 minutes. Strain out the solids and return the sauce to the pan to keep warm.
After the Meatloaf has rested for at least 10 minutes, slice and serve with some of the sauce drizzled over the top.