Preheat your oven to 375°F (190°C). Slice the zucchinis in half lengthwise and scoop out the centers to create hollow boats, leaving about ¼ inch of flesh around the edges. Place them cut-side down on a baking sheet lined with parchment paper.
Heat olive oil in a sauté pan over medium heat. Add the minced garlic and cook until fragrant, about 30 seconds. Add the sliced mushrooms and cook until they release their moisture and turn golden, about 5 minutes.
Stir the chopped spinach into the mushrooms and cook until wilted, about 2 minutes. Remove the mixture from heat and let it cool slightly.
Transfer the mushroom and spinach mixture to a bowl. Mix in the ricotta cheese and season with salt and pepper to taste, creating a creamy filling.
Spoon the filling into each zucchini boat, pressing gently to pack it in. Carefully place the filled zucchinis back on the baking sheet.
Bake in the preheated oven for about 25-30 minutes, until the zucchinis are tender and slightly browned at the edges.
Remove from the oven and garnish with chopped fresh basil. Serve hot as a cozy but elegant main dish.
