Preheat oven to 350°F.
Press one wonton wrapper into each cup of a muffin tin. Lightly spray each with cooking spray. Bake for 5 minutes until just lightly toasted. Watch closely - they brown fast.
In a medium bowl, combine the drained spinach, chopped artichoke hearts, cream cheese, mayonnaise, sour cream, Parmesan, minced garlic, garlic powder, salt, and pepper. Mix until evenly combined.
Scoop the filling evenly into each pre-baked wonton cup. Do not overfill.
Bake for 10 minutes, or until the wonton cups are golden brown and crispy and the filling is hot. Keep an eye on them toward the end.
Let cool slightly in the muffin tin, then carefully remove. Use a butter knife to gently loosen any that stick. Serve warm.