Description

Tender chicken breasts are marinated in a tangy, sugar-free mustard sauce, then topped with sautéed mushrooms, crisp bacon, and melted cheddar. This satisfying, low-carb dish delivers layered, robust flavors and finishes perfectly in the oven.

Ingredients

Scale

Tangy Mustard Marinade & Sauce

1/2 cup mayonnaise (115g)
2 tablespoons Dijon mustard (30g)
2 tablespoons yellow mustard (30g)
1 tablespoon powdered erythritol sweetener (12g)
2 teaspoons apple cider vinegar (10ml)
1/2 teaspoon garlic powder (2g)
1/4 teaspoon smoked paprika (1g)

The Chicken & Toppings

4 thin-cut chicken breasts, about 1.5 lbs total (680g)
1/2 teaspoon kosher salt (3g)
1/2 teaspoon garlic powder (2g)
1/4 teaspoon black pepper (1g)
1/4 teaspoon onion powder (1g)
4 slices thick-cut bacon (115g)
1 tablespoon unsalted butter (14g)
8 oz sliced button mushrooms (225g)
1 1/2 cups shredded sharp cheddar cheese (170g)
2 scallions, thinly sliced (for garnish, optional)

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Instructions

Prepare the sauce: In a small bowl, whisk together the mayonnaise, Dijon mustard, yellow mustard, powdered sweetener, apple cider vinegar, garlic powder, and smoked paprika until completely smooth.
Marinate the chicken: Place the raw chicken breasts in a large freezer bag or shallow dish. Pour exactly half of the mustard sauce over the chicken, turning to coat. Seal and refrigerate for at least 2 hours. Cover and store the remaining half of the sauce in the refrigerator to use for serving.
Crisp the bacon: Place a large skillet over medium heat and add the bacon slices. Cook for about 6 to 8 minutes, turning occasionally, until crispy. Transfer the bacon to a paper towel-lined plate, leaving about 1 tablespoon of the rendered bacon fat in the skillet. Break the cooled bacon into large pieces.
Sauté the mushrooms: Add the unsalted butter to the bacon fat in the skillet. Toss in the sliced mushrooms and sauté for 5 to 7 minutes, until they are tender and lightly browned. Remove the mushrooms from the skillet and set aside. Wipe the skillet clean if necessary.
Sear the chicken: Preheat your oven to 400°F. In a small bowl, combine the kosher salt, garlic powder, black pepper, and onion powder. Remove the chicken from the marinade (letting excess drip off) and sprinkle both sides with the seasoning blend. Heat the skillet over medium-high heat. Sear the chicken for 2 to 3 minutes per side, just until a golden-brown crust forms.
Assemble and bake: Transfer the seared chicken breasts to a 9×13-inch baking dish. Spoon the sautéed mushrooms evenly over each piece of chicken. Layer the broken bacon pieces on top, and generously cover each breast with the shredded cheddar cheese.
Finish in the oven: Bake for 8 to 10 minutes, until the cheese is bubbling and melted, and a meat thermometer inserted into the thickest part of the chicken registers 165°F. Garnish with sliced scallions, and serve hot with the reserved mustard sauce for dipping.

Notes

Why It Works

Reserving half the sauce before marinating ensures you have a fresh, uncontaminated dipping sauce packed with sharp mustard flavor.
Searing thin chicken breasts for only a couple of minutes per side prevents them from drying out before they finish cooking in the hot oven.
Cooking the mushrooms in a blend of butter and residual bacon fat deepens the savory profile of the dish without requiring extra ingredients.

Common Pitfalls to Avoid

Overcooking the chicken: Because these are thin-cut breasts, they cook incredibly fast. Do not exceed 3 minutes per side during the stovetop sear, or they will be dry after baking.
Skipping the marinade time: The vinegar in the mustard sauce acts as a tenderizer. Giving it at least 2 hours significantly improves the final texture.
Using granulated sweetener: Granulated erythritol will not dissolve properly in the cold mayonnaise base. Always use confectioners/powdered sweetener for a smooth sauce.

Variations

Spice it up: Add a pinch of cayenne pepper to the chicken seasoning blend or stir a teaspoon of hot sauce into the mustard marinade.
Cheese swap: For a slightly different flavor profile, substitute half of the cheddar cheese with shredded Monterey Jack or Gouda.

Allergy Alert

This recipe contains dairy (butter, cheese), egg (mayonnaise), and mustard. Substitute the butter with ghee or a dairy-free alternative, and use a dairy-free cheese shred if needed. For an egg-free version, use a vegan mayonnaise alternative.

Nutrition (per serving — estimates)

Nutritional values are approximate, based on standard reference data (USDA FoodData Central). Actual values vary by brand and exact measurements. For precision, use a tracker like MyFitnessPal or Cronometer.

Nutrition

Serving Size: 1 chicken breast with toppings
Calories: 620
Sugar: 1g
Sodium: 800mg
Fat: 44g
Saturated Fat: 16g
Carbohydrates: 4g
Fiber: 1g
Protein: 52g