Cheesy Potato Casserole Recipe

Ingredients

• 1/4 cup butter, plus more for the casserole dish
• 1 yellow onion, diced
• 3 cloves garlic, minced
• 1/4 cup all-purpose flour
• 3 cups vegetable or chicken stock
• 2 cups grated cheddar cheese
• 1/2 teaspoon salt
• 1/2 teaspoon black pepper
• 30 ounces frozen hash browns
• 3 serrano peppers, sliced
• 2 tablespoons olive oil
• Coarse salt