Cook the bacon in a skillet over medium heat until crispy. Transfer to a paper towel-lined plate to drain excess grease.

To hard-boil the eggs, place them in a saucepan and cover with water. Bring the water to a boil over medium-high heat. Once boiling, reduce the heat to low and let the eggs simmer for 9-12 minutes, until they reach an internal temperature of 160°F (71°C) for safe consumption. Transfer the eggs to a bowl of ice water to cool, then peel and slice lengthwise.

Preheat the grill or a grill pan to high heat.

Season the steak with salt and black pepper on both sides.

In a small bowl, whisk together the Dijon mustard, grated garlic, lemon juice, apple cider vinegar, and extra-virgin olive oil to make the dressing.

Divide the romaine lettuce among plates. Arrange the sliced hard-boiled eggs, crispy bacon, halved grape tomatoes, cucumber, onion, diced avocado, and crumbled blue cheese over the lettuce.

Place the sliced steak on top of the salad and drizzle with the prepared dressing.

Mix the sparkling water with lemon slices.

Serve the Cobb salad alongside the lemon sparkling water.