Prep: Preheat oven to 350℉. Spray an 8x11 (or similar size) baking dish, set aside.
Sauté: Bring a small cast iron skillet to medium high heat and add 1-2 teaspoons olive oil. Once hot, add 4 tablespoons shallots and 2 teaspoons garlic. Move around pan until garlic is fragrant and shallot has softened, approx. 1-2 minutes.
Artichoke Mixture: In a medium mixing bowl, add cooked garlic and shallot, ½ cup plain greek yogurt and ¼ cup + 2 tablespoons mayo. Stir to combine. Fold in 1/2 cup of mozzarella cheese, 15 ounces can artichokes, 10 ounces frozen spinach, ¼ cup parmesan cheese, ½ teaspoon kosher salt, ¼ teaspoon lemon juice, ⅛ teaspoon ground black pepper and scant lemon zest.
Bake: Pour out into prepared 8x11 pan (or similar size). Top with remaining 1/2 cup mozzarella cheese. Place in oven, middle rack, uncovered for 15 minutes or until cheese is melted and bubbly. Feel free to place under the broiler for 1-2 minutes if you want to brown a bit, just watch very carefully.
Serve: Remove from oven and let cool slightly. Serve with cut up veggies, pita bread, crackers or easy homemade crostini.
Notes
Make Ahead: you can easily make this ahead of time and stop at Step 4, cover with foil and place in the refrigerator until you want to bake - you might just need to cook a bit longer in the oven to account for it coming out of the fridge cold.
Storage: store leftovers in an airtight container in the refrigerator for up to 3-4 days.