Cook and crumble sausage in a large skillet over medium-high heat until browned and crisp, about 5-7 minutes without draining fat.
Sprinkle flour over sausage, stir, and cook 2-3 minutes to remove raw flour taste.
Slowly whisk in milk, reduce heat to medium-low, and stir until gravy thickens, about 4-5 minutes.
Remove gravy from heat and stir in seasoned salt, black pepper, and optional herbs; set aside.
Scramble eggs in a separate pan to desired doneness; set aside.
Preheat oven to 375°F. In a large bowl, combine flour and salt; cut in vegetable shortening and cold butter until mixture forms pea-sized crumbs.
Whisk egg, vinegar, and cold water in a small bowl; add to flour mixture and stir until dough forms.
Divide dough in half; roll one portion on a floured surface to about 1/8-inch thickness and cut into 3x4-inch rectangles.
Place half the rectangles on a parchment-lined baking sheet; brush edges with egg wash.
Add scrambled eggs and sausage gravy to center of each rectangle, then cover with a second rectangle and crimp edges with a fork.
Brush tops with egg wash; sprinkle with shredded cheese and seasoning blend.
Bake for 25 minutes or until golden brown.
Cool pop-tarts for 5 minutes before serving warm.