Best Cream Of Broccoli and Potato Soup

INGREDIENTS

• 2 tablespoons butter
• 1 onion, chopped
• 5 cloves garlic, crushed
• 1 large white potato, cubed
• 8 cups broccoli florets and stems
• salt and ground black pepper to taste
• 3 cups chicken broth
• 3 tablespoons butter
• 3 tablespoons all-purpose flour
• 1 cup milk
• 1 cup heavy whipping cream