Build the flavor base – Heat olive oil in a skillet over medium heat. Add the chopped onion and cook for 5–6 minutes until soft and translucent. Stir often to prevent browning, allowing the onion to turn sweet and mellow.

Release aromatics – Add the minced garlic and cook for about 30 seconds until fragrant. Keep the heat moderate so the garlic doesn’t burn.

Prepare the vegetables – Stir in the spinach and chopped artichokes, mixing well so they warm through and combine evenly with the onion mixture. Remove from heat.

Create the creamy base – In a mixing bowl, combine softened cream cheese, sour cream, and mayonnaise. Mix until smooth and cohesive.

Combine everything – Fold the warm spinach-artichoke mixture into the creamy base. Add Parmesan, mozzarella, salt, and black pepper, stirring gently until evenly distributed.

Bake until bubbly – Transfer the mixture to a baking dish and bake at 375°F (190°C) for 25–30 minutes, until hot throughout and lightly golden on top.

Rest briefly – Let the dip sit for a few minutes before serving so it sets slightly and scoops cleanly.