In a food processor, add onion and pulse until chopped well.
Place chopped onion in a paper towel and squeeze out all the liquid.
Return into food processor with garlic, herbs, salt and black pepper and pulse until garlic is minced.
Add ground lamb meat and pulse until well combined.
Place mixture into a loaf pan evenly and press firmly.
With a piece of foil, cover the loaf pan tightly and with a fork, poke a few vent holes into foil.
Arrange the trivet in the bottom of Instant Pot. Add 1½ cups of water in Instant Pot.
Arrange the meatloaf on top of trivet.
Secure the lid and cook under “Manual” and “High Pressure” for about 20 minutes.
Select the “Cancel” and carefully do a Natural release.
Preheat the oven to broiler.
Remove loaf pan and place onto a wire rack to cool for about 15 minutes.
Carefully, remove meatloaf from pan and transfer onto a broiler pan.
Broil for about 2-3 minutes.
Remove from oven and immediately, top with feta cheese.
Cut into desired sized slices and serve.