• Preheat oven to 425°F Prepare a baking sheet with a wire rack set on it. This will keep the artichoke packets elevated so the heat can circulate under and around to cook the artichokes evenly.
• In a large bowl prepare a lemon water bath with the water and juice of 2 lemons. The acid in the water will keep the artichokes from discoloring.
• Wash the artichokes under cold tap water while brushing them with a soft vegetable brush.  This will remove the natural bitterness on the outside.  
• Slice off the stems ends and with a serrated knife cut 1/2-inch off the top trim of the artichoke.  Using scissors trim the tips of the artichoke leaves. 
• Add the trimmed artichokes to the lemon water bath.Working with one artichoke at a time, drain and pat dry with paper towels and brush the entire artichoke with olive oil.  
• Cut two lemons in half and squeeze 1/2 of a lemon on the top of the trimmed artichoke. 
• Stuff slivered garlic between the top leaves of the artichoke.
• Add a piece of butter and one or two slices of lemon to the top of the artichoke and Sprinkle with salt
• Double wrap artichoke with layers of heavy duty foil. Sealing well on top by twisting and pinching foil packet. 
• Continue the process with the remaining artichokes.

Roasting the Artichokes:

• Place foil packets of artichokes on a wire rack set over a baking sheet, in the oven and bake for 45-60 minutes, depending on the size.  
• Test for doneness by unwrapping the foil and pulling a leaf from the center of the artichoke.  If the leaf removes easily or with a little resistance, unwrap and enjoy.  If difficult to remove a leaf, rewrap in the foil and bake for an additional 5-10 minutes.  
• Remove Artichokes from oven. When cool enough to handle, unwrap artichokes and enjoy with Lemon-Garlic Aioli.

For the Garlic-Lemon Aioli:

• In the blending container of a mini-food processor combine the garlic, lemon juice, mustard, and egg yolks. 
• Process in short pulses until smooth.  With the motor running, add the oil in a slow, steady stream and process until smooth and blended. 
• Season with salt and pepper.
• Transfer the aioli to a small bowl, cover and refrigerate until ready to serve.