Preheat oven to 450. Pulse garlic cloves in a food processor. Add in portobello mushrooms and pulse until fine. Next, mix in the egg and 1 tbsp of the ketchup.

In a bowl, add mushroom mixture, beef, panko, and parsley. Season with salt & pepper. Use your hands to mix together until well combined. In a large casserole dish, form the mixture into a loaf about 1” high.

Spread the ketchup all over the meatloaf. Bake in the oven for 20 minutes at 450 degrees Fahrenheit.