In a bowl, combine and toss drained and rinsed artichoke bottoms with lemon juice. Set aside.
In a large frying pan over medium heat, sweat onions in oil until translucent. Add tomatoes and cook until heated through, about 1 minute. Stir in Italian seasoning and shredded basil leaves. Add in artichoke bottoms with lemon juice and sprinkle with salt and pepper. Cover pan and reduce heat to low. Simmer for 10 minutes.
To serve, remove artichoke bottoms and place on serving plate so the hollow side is up. Fill with tomato-onion mixture.