Preheat oven to 350 F.
Heat olive oil in a large skillet.
Add onions, peppers and celery and saute until tender.
Add garlic and cook just until fragrant.
Remove from heat and let cool. Set aside.
In a large bowl, add breadcrumbs and just enough milk to moisten the crumbs.
Add remaining ingredients, except for the beef.
Mix these ingredients well.
Add the beef. Use your hands to mix it in. Don't be alarmed if the mixture seems a bit too wet at first. Handle the beef as little and as gently as possible to prevent it from becoming tough when baked. Mix JUST until everything is combined.
Optional: Fry a tiny piece of the mixture to check the taste and adjust the seasonings if desired.
When all of the ingredients are well combined, spoon the mixture into a loaf pan and smooth to an even layer. Set aside.
To make the glaze, combine all glaze ingredients and spread half on top of meatloaf.
Bake for 30-35 minutes and then top with remaining glaze. ( you don't have to use all of the glaze. You can save some to use when serving the meatloaf of desired)
Continue baking for another 30-35 minutes or until internal temperature reaches 160 F. or to your desired (safe) doneness. ( I like to flip the oven to broil for the last few minutes to get the glaze a bit sticky but watch it carefully if you decide to do this)
Remove from oven, drain off the fat and let meatloaf rest before slicing. (If meatloaf is steaming hot when you cut into it, it will fall apart)