I start by heating the olive oil in a skillet over medium-high heat. Once it shimmers, I add the mushrooms and let them cook undisturbed for a few minutes so they develop a golden sear. Then I stir in the garlic and onions, letting their flavors bloom without burning—this base layer gives so much depth.
After the mushrooms have some color, I push them to one side and add the ground beef. I resist the urge to stir immediately—I let it sit for a minute or two to form tasty browned bits. Then I break it up and cook until there’s no pink. If there's excess fat, I drain it now to keep the sauce from becoming greasy.
Next, I mix in the condensed cream of mushroom soup, starting with half a can of water. Then I stir the mushrooms back in. The mixture simmers gently to warm through and marry the flavors. I taste and season with salt and pepper here. If it feels too thick, I slowly whisk in a little more water until it's just saucy enough.
Once the sauce is bubbly, I sprinkle the mozzarella evenly over the top and cover the skillet briefly so the cheese melts into gooey deliciousness. To finish, I scatter chopped parsley for a fresh, bright contrast. Then I serve it straight from the skillet over rice, pasta, mashed potatoes, or even baked potatoes—comfort in a bowl.