Preheat oven to 425°F. Fill a medium bowl halfway with water. Add 3 tablespoons lemon juice. Set aside.

Peel off a few layers of the tough, dark outer leaves from the artichokes, until you get to the lighter green leaves. Trim the stem, if present, so about a 1/2 inch remains. Cut off and discard the top 1/4 of the artichokes then slice the artichokes in half lengthwise. As they’re sliced, place the halved artichokes in the lemon water, cut side down.

Drain artichokes and pat dry. Combine artichokes, oil, salt, pepper and garlic in a bowl; toss to coat. Heat a large ovenproof skillet over high heat. Add the artichoke mixture to pan; cook 1 minute, 30 seconds on each side or until lightly browned. Remove from heat.

Add the lemon slices and thyme or rosemary. Bake at 425°F for 16 to 20 minutes, stirring once half way through. Remove thyme or rosemary stems; sprinkle the leaves over the artichokes and discard the stem. Discard stem and any blackened lemon.

Arrange artichokes on a serving platter, sprinkle with remaining 2 teaspoons lemon juice and the lemon zest. Season with salt and pepper, if desired, before serving.