Almost-Famous Spinach-Artichoke Dip

INGREDIENTS

• 1 clove garlic, minced
• 2 tablespoons minced onion
• 2 10-ounce bags spinach, stems removed
• 1 1/4 cups whole milk
• 1/2 cup shredded white sharp cheddar cheese
• 2 teaspoons all-purpose flour
• 1 tablespoon unsalted butter
• 1 teaspoon Worcestershire sauce
• 1/2 cup frozen artichoke hearts, thawed, squeezed dry and roughly chopped
• 1/2 teaspoon fresh lemon juice
• 1 1/4 cups grated parmesan cheese
• Tortilla chips and salsa, for serving
• 1/4 cup sour cream, plus more for serving
• Kosher salt