Cook the ground beef in a saucepan over medium heat until browned, stirring often to break up any chunks, takes about 10 minutes.
Add the onions, celery, bell peppers, and garlic, then cook until softened, about 5 minutes.
Add the pasta sauce then bring to a simmer. Cover and cook to meld the flavors, for at least 30 minutes.
Béchamel Cheese Sauce
In a cup combine 1/2 a cup of the milk with the cornstarch and beat with a fork until smooth.
Bring the remaining milk to almost a boil in a pot. Just before boiling stir in the cornstarch mixture. Continue stirring until thickened.
Add the shredded cheese and continue stirring until it is completely melted and well combined. Remove from the heat until needed.
To Assemble
Preheat a camp oven, closed barbecue, or smoker to 350 degrees F (180 degrees C).
Add a layer of béchamel sauce to a baking tray. Add a layer of pasta and bolognese sauce. Continue this ordering trying to evenly distribute the sauces through the baking dish. Finish with a béchamel layer.
Evenly sprinkle the breadcrumbs over the top, then evenly sprinkle with the cheese. Finally, top with the herb rub.
Place the lasagna in the preheated camp oven and bake for 40 minutes. Check regularly, if the top is getting too brown, cover with a piece of foil. It is cooked when a knife enters the center of the lasagne and the resistance indicates the pasta sheets are softened and ready to eat.
When cooked remove from the heat and let cool slightly before serving.