In a small mixing bowl, combine ¼ cup of softened unsalted butter, 2 crushed garlic cloves, and 2 tablespoons of finely chopped fresh dill. Mix until smooth and set aside.

Place ribeye steak in the freezer for 20 minutes. Remove and slice against the grain into thin strips.

Heat a skillet over high heat, add oil, then the sliced steak and sprinkle with salt. Cook for 3-4 minutes until golden.

In the same skillet, add sliced onion and a pinch of salt. Cook for 5-7 minutes until caramelized.

Slice the baguette open lengthwise and spread the herb butter on both sides. Layer with steak, caramelized onions, and havarti cheese.

Preheat broiler to high. Place the assembled sandwich on a baking sheet and broil for about 2 minutes until cheese is bubbly.

Remove from oven, let cool slightly, slice into portions, and serve warm.