Add olive oil and coat sides and bottom of the crock. Put on HIGH and add onion. Let cook until transparent

Add garlic, fresh spinach (if using fresh) and artichokes. Let cook until spinach is wilted and/or liquid is boiling. (If using frozen spinach, squeeze the excess moisture from the spinach and place in the slow cooker after artichokes are hot.)

Add sour cream (yogurt), cream cheese, mayonnaise, Parmesan, fontina, wine and pepper, and stir to combine.

Cover and cook on the HIGH setting, stirring occasionally as the cheese melts, until heated through and bubbling around the edges, about 2 hours. If too thick, add a little milk.

Uncover, add the lemon zest, and stir to incorporate the cream cheese. Sprinkle green onions on top. The dip is ready to be served and can be left covered on the WARM setting for up to 2 hours.

You can eat this dip straight from the pot (or transferred to a serving bowl), or transfer dip to a small ovenproof skillet (or ramekins). Place in oven and broil until the top is golden and the dip is bubbling, 5 to 8 minutes. Let sit a minute or two before serving.

Leftovers can be stored in an airtight container in the refrigerator for up to 4 days. The dip is also delicious served cold. I usually freeze half of it for a later date.

From Comments (I haven't tried it): A 4-oz. can of chopped green chilies is a wonderful addition.