In a large saucepan, brown your ground beef, and stir in the diced onion and minced garlic and cook together until the onions are translucent then drain off the grease. Add the meat back to your pan.
Pour in your entire jar of pasta sauce and Italian seasonings, then mix together. Remove from the heat and set aside.
Boil some water and cook your spaghetti noodles al dente for about 7 minutes.
While the noodles are boiling, make your alfredo sauce by melting one stick of butter in a large pan, then slowly adding your heavy cream and whisking the two together as you bring the sauce to a light simmer. Add your garlic powder and pepper to taste. Turn off the heat, then add in your parmesan cheese and combine until fully melted and incorporated.
Drain your noodles and pour them into the pan with the alfredo sauce and mix together. Pour the alfredo covered spaghetti into a lightly sprayed 9X13 casserole dish or foil pan.
Next spoon your spaghetti and meat sauce all over the top of the alfredo noodles, DO NOT MIX, just layer it on top.
Finally, cover with shredded cheese and bake in the oven for 20-25 minutes or until golden and bubbly.