In a 13x9" ungreased baking pan combine the beef & pork.Mix in the eggs and breadcrumbs by hand until mixed thoroughly, reserve. In a 1 qt saucepan combine 3 tb butter with the onions, celery, green pepper, worcestershire , tabasco and meat seasoning mix. Saute over high heat for 5 minutes, stirring frequently and scraping the bottom well. Remove from heat and let cool. Add mixture and 1/4 c milk to the meat mixture and mix well by hand. Form into a 12X8 loaf and center in the pan.Bake in a 450 oven for 30 minutes, remove from oven and pour off drippings, reserving 2 1/2 tb drippings.Set meat and drippings aside. Boil the potatoes until fork tender, drain reserving 1 c potato water.Place the potatoes while hot in a large mixing bowl. Add remaining butter, 1/2 c milk salt & white pepper.
Stir with wooden spoon until broken up then beat with a whisk or hand held mixer.If potatoes are not creamy enough beat in some of the reserved water.
In a large skillet combine the reserved drippings with the carrots, onions and veg. Seasoning mix. Saute over high heat for 1 1/2 minutes stirring frequently.
Add zucchini and yellow squash and continue saute until noticably bright in color, about 3-4 minutes stirring once in a while. Remove from heat. Mound the cooked vegetables on top of the meat loaf, keeping away from edges. Layer the mashed potatoes evenly over top of of the vegetable layer and top edges of meat, using all of the potatoes.
Bake at 525 until brown on top about 8-10 minutes.