In addition to their use in this French onion tart, these melted onions can be the basis for a French onion soup or a condiment to roasted and grilled meats.
8 large yellow onions
2 tablespoons unsalted butter
How To Make
Cut to remove the top and bottom (root end) of each onion. Standing the onion on the flat cut, cut the onion lengthwise into halves. Remove the outer peel. Lay the onion half cut side down with the root end toward you. Slice the onion halves down the center to make quarters. Remove the core (root side) by making a small V incision into each quarter onion and discard. With the root or opposite end facing toward you slice along the grain lines into ¼ inch thick slices. Repeat with remaining onions.
Melt the butter in the stockpot over medium-low heat. Add the sliced onions. Keep your eye on the onions and stir often at the beginning to allow all the slices to have contact with the bottom of the pot so they start to release their liquid. In about 45 minutes they should have released a good amount of liquid. At this point, you can turn the heat up slightly to reduce this liquid at a quicker pace. Return the heat to low once most of the watery liquid is gone.
Place the diffuser under the stockpot to further reduce the heat in contact with the bottom of the pot. Reduce heat to low and stir every ten to 15 minutes, watching to keep from scorching. The color will change from white to ecru to amber to finally a deep brown. This will take five to six hours. Keep a careful eye toward the end to prevent any scorching, stirring much more often as you get toward the end. You will remove from the heat when you have approximately 1 ½ to 2 cups of deeply caramelized onions.
Enjoy them warm, or set them aside to cool for use in other recipes like the Onion Tart.