This sounds like a really good casserole, quick and easy to make. And as a bonus, a cornbread topping. On my to cook list. The time for prep or cook does not include the time to cook the pinto beans. This is a 3 step process, 1. cook beans, 2. prepare other items on stove top in a pot, 3. bake in the oven. Links to the shortcuts are listed in the Recipe Notes section.
First order of business, need to get those pinto beans cooked, use what ever method you prefer, stove top, slow cooker, or my preferred way is the pressure cooker. Drain and set the beans aside.
Preheat your oven to 200 C (400 F).
In a large pot, cook the ground beef, onion, and garlic, break up the beef as you cook, when browned and cooked through, drain the fat then add the cooked beans, jalapeno, tomato and tomato sauce, and mix together.
Pour mixture into a heat proof baking dish and spread out evenly. I will guess a 7×11 or 9×13, and I will clarify this when I make it.
Mix together the Jiffy mix, egg, and milk, pour over the meat and bean mixture.
Bake for about 15 to 20 minutes or until the cornbread is lightly browned.
Serve. I would serve this with mashed potatoes or a nice green salad.