Wash artichokes under cold water. Using a heavy stainless steel knife cut off the stems about 1/2 inch from the base. Pull off the lower petals that are small and tough. Cut off the top inch of the artichoke. Trim the thorny tips of the petals with kitchen shears.
Place the artichokes, bottom up, in the inner pot of the Instant Pot fitted with a steamer basket and 2 cups of water .
Choose the “Steam” setting and reduce cooking time to 8 minutes.
While the artichokes are steaming prepare the marinade by placing the lemon juice, balsamic vinegar, olive oil, oregano, garlic, salt, and pepper in a small jar with a lid. Shake well to incorporate all of the ingredients. Set aside.
When the “Steam” cycle is complete, release the pressure and carefully remove the artichokes.
Allow to cool slightly so you can handle them. Cut the artichokes in half. Remove the center cone of purple prickly leaves. This is the choke that protects the heart. Now, scrape away the thistle fuzz covering the artichoke heart. The heart is the meatiest part of the artichoke.
Drizzle the marinade over the warm artichokes. Turning to make sure to coat them well with marinade. Allow them to sit for 30 minutes to overnight.
When ready to serve, sear artichokes cut side down on a grill pan or BBQ for 3 to 5 minutes. Enjoy!