Heat 2 tablespoons olive oil in a large saucepan over medium heat. Add the minced onion and garlic; cook for 5 minutes until softened.

Add the chickpeas, broth or water, and salt and pepper to taste. Cook for 10 to 15 minutes until chickpeas are softened.

Blend the mixture using an immersion blender or regular blender until smooth.

Bring the mixture to a boil and slowly whisk in the polenta. Decrease the heat to medium and stir constantly for 15 to 20 minutes until thick.

Pour the cooked polenta into a lightly greased rimmed baking sheet, spread evenly, cover with foil, and refrigerate for 2 to 3 hours until chilled and set.

Preheat the oven to 400°F (200°C). Toss the diced squash with 3 tablespoons olive oil, salt, and pepper.

Roast the squash for about 30 minutes, stirring occasionally, until soft.

Once the polenta is set, cut it into 2 to 3-inch discs using a cookie cutter or slice it into squares.

Place the discs on a lightly greased baking sheet and brush the tops lightly with olive oil.

Bake the polenta discs for about 30 to 40 minutes, until golden brown on the top and slightly crispy.

Top each polenta disc with a piece of roasted squash and a sprig of rosemary.