Heat the oven to 450°F.

• Scrub or peel the carrots and trim the ends; cut any smaller carrots in half lengthwise and any larger carrots in quarters lengthwise.
• Trim the ends from the Brussels sprouts. Cut the sprouts in half lengthwise.

On a sheet pan, toss the carrots and Brussels sprouts with 1 to 2 tablespoons oil; season with salt and pepper and spread in an even layer. Roast, stirring the vegetables halfway through, until tender and lightly browned, 12 to 15 minutes. Remove from the oven, add the shallot-garlic confit, and toss until the vegetables are coated. 

While the vegetables are roasting, prepare your protein.

In a large frying pan over medium-high heat, warm 1 to 2 teaspoons oil until hot but not smoking.

For chicken:

• Pat the chicken dry with a paper towel; season generously with salt and pepper.

Add the chicken to the pan and cook, turning once, until lightly browned, 1 to 2 minutes per side. Reduce the heat to medium-low and continue cooking, turning occasionally, until firm and cooked through, 5 to 8 minutes. Transfer to a plate to rest for 5 minutes. Cut the chicken into ½-inch thick slices. Do not clean the pan.

For salmon:

• Pat the salmon dry with a paper towel; season lightly with salt and pepper. 

Add the salmon to the pan and cook until lightly browned, 4 to 5 minutes. Turn and cook until the flesh is opaque and flaky, 2 to 4 minutes. Transfer to a plate. Do not clean the pan.

While your protein is cooking, make the truffle cauliflower mash.

• Cut the cauliflower lengthwise into quarters, discarding any leaves or thick stalks. Using a food processor fitted with the grater attachment, or the coarse holes of a box grater, coarsely grate the cauliflower. Alternatively, using a knife, cut the florets and tender stems into ¼-inch pieces. 

In a medium [large] sauce pot over medium heat, add the cauliflower, cover with about a 1-inch deep layer of water, and bring to a simmer. Cover and cook until the cauliflower is fork-tender, 8 to 10 minutes. Remove from the heat. Strain the cauliflower and shake off as much excess water as possible. Return the cauliflower to the pot, then mash it with a fork or masher. Add the truffle butter and stir until thick and creamy. Season to taste with salt and pepper. Cover to keep warm.

In the same pan used for your protein, add the demi-glace and 2 tablespoons [¼ cup] water. Bring to a boil, reduce to a simmer, and cook for 30 to 60 seconds.

Spoon as much demi-glace as you like down the center of individual plates and top with your protein. Arrange the roasted vegetables and truffle cauliflower mash on either side. Serve any remaining demi-glace on the side.