1) Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper.
2) Place artichoke bottoms in a bowl and toss with the lemon juice. Let sit for 5 minutes. Rinse the artichokes with cold water and pat dry. Top each artichoke with half a roasted tomato, a mozzarella ball, and a teaspoon of pesto. Roast in the oven for about 5 minutes, til cheeses melts.. Serve immediately.