Apply Sauce & Finish in Oven:
Heat up the pressure cooker over medium-low heat. (Instant Pot
: press Sauté, then Adjust button to Saute More Function) Bring the tomato sauce to a simmer and reduce until desired consistency (roughly 5 – 8 minutes). Brush the thickened tomato sauce over the whole meatloaf with a silicone basting brush
. Place the meatloaf in the oven on the top rack for 10 – 15 minutes.