For the Sage Brown Butter:

1. In a large pot, heat the butter over medium-low heat.
2. Once the butter is melted, add the garlic and sage leaves.
3. Cook, stirring almost constantly, until the butter just starts to turn brown and smells nutty. Remove from heat and stir in the salt.
4. Remove 3 tablespoons of the butter, along with the crispy sage leaves, to use for the croutons. The remaining butter will be used to make the soup.

For the Soup:

1. To the brown butter left in the pot, add the olive oil and return the pot to medium heat.
2. Add the onion, garlic, and spices and cook until the onion is beginning to soften, about 5 minutes.
3. Stream in the dry sherry and cook until mostly evaporated, about 2 minutes.
4. Add the stock, beans, and pumpkin puree and stir until well combined.
5. Bring the mixture to a simmer and cook, stirring frequently, for about 15 minutes. While the soup simmers, make the croutons (following the steps listed below).
6. Remove the pot from the heat and puree the soup using an immersion blender or by transferring the soup in batches to a blender or food processor.
7. Stir in the maple syrup, vinegar, and half-and-half. Check for seasonings and keep warm until ready to serve.

For the Croutons:

1. Preheat the oven to 375°F and line a baking sheet with foil. Spread the cubed bread out in an even layer on the tray.
2. Pour over the reserved brown butter, setting the sage leaves aside for garnishing the soup. Season with salt and pepper and toss the bread cubes with your hands until everything is evenly coated in the butter and well seasoned. 
3. Bake for 15-20 minutes, shaking the pan occasionally, or until the croutons are golden and crisp.

Serve the soup hot garnished with the croutons and crispy sage leaves.