Hamburger Steaks with Creamy Mushroom Gravy

Ingredients

• 1.3 pounds ground beef
• 4 tbsp panko breadcrumbs
• ½ tsp garlic powder
• ½ tsp dried onion
• 1 tsp salt
• 1 tsp black pepper
• 2 tbsp heavy cream
• 1 egg
• 2 tsp Worcestershire sauce
• 1 tbsp olive oil
• 2 tbsp unsalted butter (divided)
• 9 ounces mushrooms (sliced)
• 1 small yellow onion (diced)
• 2 garlic cloves (minced)
• 1 tsp dried thyme
• 2 tbsp all-purpose flour
• 1 tbsp Worcestershire sauce
• ½ cup vegetable broth (or beef broth)
• 1 cup heavy cream
• 2 tbsp chopped parsley (for serving)