Make the smashed potatoes: You can do some of this ahead of time if you want. Place the potatoes (whole) in a saucepan and cover with water. Place over a burner on medium-high and boil/simmer until they are knife-tender (it's better to err on the side of over-soft). This is usually 15-25 minutes.
Drain and cool slightly until you can handle them. You can also put them in the fridge until you need them. When ready to use, smash them using the bottom of a glass or other flat surface (I do mine on parchment paper).
Spray lightly with olive oil and then sprinkle with salt, pepper, garlic powder, and a bit of paprika. Air fry for 7-12 minutes, until they become crispy and golden (you can also do this in the oven at 425 F, it will take longer).
Make the hamburger and sauce: Cook the ground beef on medium, breaking it into small chunks. Season well with salt. When the beef is cooked through and starting to develop nice browning and a bit of crisp, add the beef broth, tomato paste, and mustard and stir together. Cook for another minute or two, then remove from heat.
While the beef is cooking, whisk together the sauce ingredients. Taste and adjust as needed. Chop or prep any other fixin's as needed.
Assemble your bowls: Put smashed potatoes at the bottom of the bowl, top with hamburger mixture, then add fixin's and drizzle with sauce. Eat while hot!