Saus Prancis Portobello dengan Aioli Lobak

Bahan-bahan (4 porsi)

• 4 portobello mushroom caps, sliced into thin strips
• 2 -3 tablespoons olive oil
• 1 -2 teaspoons Montreal steak seasoning (or just a sprinkle of salt and pepper)
• 2 tablespoons butter
• 1 large onion, thinly sliced
• 1/4 cup white wine
• 1 tablespoon Worcestershire (omit for vegetarian / vegan)
• 1 tablespoon soy sauce
• 2 cups beef or vegetable broth
• salt, pepper, and a pinch of sugar to taste
• 1/2 cup mayo
• 1 teaspoon horseradish
• 1 clove garlic, grated
• pinch of salt
• 4 crusty sourdough rolls, or a baguette cut into 4 sections
• Provolone cheese slices