Preheat your oven to 375°F (190°C) for even baking.
Slice the baguette in half lengthwise and hollow out some of the bread if desired.
Sauté chopped shallots and minced garlic in a skillet with oil until translucent, about 2-3 minutes.
Mix chopped artichoke hearts, spinach, sautéed shallots and garlic, Greek yogurt, mayonnaise, Parmesan, and mozzarella in a bowl until combined.
Spread the filling evenly across the cut sides of the baguette, packing it in nicely.
Place the filled baguette on a baking sheet and bake for 20-25 minutes until golden brown.
Let cool for a few minutes, slice, and serve warm.