Mix ½ cup of softened unsalted butter with 2 cloves of minced garlic and 2 tablespoons of chopped fresh dill in a bowl until creamy and well incorporated.

Place your steak in the freezer for 15-20 minutes until firm but not frozen solid, then slice thinly against the grain.

Heat 1 tablespoon of oil in a large skillet over medium-high heat. Add the seasoned steak strips in a single layer, cooking for 2–3 minutes on each side.

In the same skillet, add 1 large sliced yellow onion, reduce heat, and sauté for about 10 minutes until soft and golden brown.

Cut a fresh baguette in half lengthwise, spread herb butter on both halves, layer cooked steak strips, caramelized onions, and melted Havarti cheese.

Preheat your broiler on high, place the sandwich halves on a baking sheet, and broil for about 2 minutes until cheese is melted.

Remove from oven, let cool slightly, slice into portions, and serve with a sprinkle of fresh parsley or dill.