Preheat oven to 400°F.

Cut the top off the head of garlic, drizzle with olive oil, wrap in foil, and roast for 45 minutes until soft and golden.

On a separate tray, toss cherry tomatoes with olive oil, balsamic vinegar, and salt. Roast at 400°F for 20–25 minutes, until blistered and softened. Stir gently once finished.

In a skillet over low heat, add butter and olive oil. Add sliced onions with a pinch of salt. Cook for about 45 minutes, stirring every few minutes, until deeply golden and caramelized.

Season steak generously with salt and pepper. Heat olive oil in a pan over medium-high heat. Sear steak 3–4 minutes per side. After flipping, add butter and baste continuously until desired doneness. Rest 5–10 minutes, then slice thinly.

Squeeze roasted garlic into a bowl. Mash and mix with mayonnaise, parsley, lemon juice, salt, and red chili flakes.

Lightly toss arugula with olive oil, salt, and pepper.

Toast sourdough bread. Add provolone and toast until melted. Spread roasted garlic mayo on the bread, layer with sliced steak, caramelized onions, roasted tomatoes, and seasoned arugula. Top with remaining bread and serve immediately.