Preheat the oven to 425°F/220°C/gas mark 7. Line a large baking sheet with parchment paper.
Carefully cut the pumpkin in half and scoop out the seeds and stringy bits. Slice each pumpkin half into 1"(2.5 cm) thick strips. Arrange the strips on the baking sheet. Brush all sides of the flesh with 2 tablespoons of oil. Set aside.
Keeping the garlic bulb intact, slice the tops off of the garlic cloves with a large knife. Drizzle the cloves with 1 teaspoon (5 mL) of oil. Wrap the garlic bulb in foil and set on the baking tray with the pumpkin. Roast in the preheated oven for 30-40 minutes, flipping the pumpkin after 20 minutes. The pumpkin is cooked once the flesh is easily pierced with a fork and some caramelization is visible. The garlic is cooked once the cloves are soft and golden. If your garlic bulb is really big, you may need to roast it longer.
Open the foil packet around the garlic bulb. Allow the pumpkin and garlic to cool until you can safely handle it, about 10 minutes. Remove the peel from the pumpkin strips with a small knife, discarding the skin (this is not edible for most pumpkins). Use the tip of the knife or your fingers to remove the soft garlic cloves.
Make the Pumpkin Soup
In a Dutch oven or large heavy-bottomed pot over medium heat, add 2 tablespoons (30 mL) oil. When the oil is shimmering, add the onions, apples, cinnamon, cayenne pepper, and ginger, stirring occasionally for 5-8 minutes or until the onion is translucent and the apple softened. Deglaze with the beer (or substitute per ingredient list.)
If you have a high-powered blender, add the cashews to the pot (if you don't have a high-powered blender, see Notes below.) Reduce the heat and simmer until the moisture is reduced by about half, about 5 minutes. In the meantime, peel the skin off the pumpkin wedges and discard the skins. Remove the skin from the roasted garlic cloves.
Add the pumpkin flesh, roasted garlic, and the onion-cashew mixture from the pot to a blender with 2 cups (500 mL) of broth. If you have a small blender, you'll need to do this in batches. It's not safe to overfill a blender with hot liquids as the steam creates pressure and can pop the lid off, spraying scalding liquid on you.
Add the pumpkin soup and remaining 1 cup (250 mL) of broth back to the pot over medium heat - bring to a boil then reduce to a simmer for about 10 minutes to bring the flavors together. Stir occasionally. If using canned coconut milk or non-dairy milk instead of cashew cream, add it in at this time. If you'd like to thin the soup, add a bit more broth. If you'd like to thicken the soup, allow it to simmer until thickened as desired. Add salt and pepper to taste.
If serving at the table, transfer the soup to a terrine. Otherwise, ladle the soup into serving bowls. Garnish with toasted pepitas, crispy chickpeas, or a dollop of unsweetened vegan yogurt/sour cream or a drizzle of canned coconut milk, as desired.
Store cooled soup in an airtight container for up to 5 days in the refrigerator. May be frozen in an airtight container for 3-6 months.
Don't Have an Apple? Substitute an apple with 1/2 cup (125 mL) unsweetened applesauce, adding it to the pot after deglazing. Cashews:If you don't have a high-powered blender, you will need to soak your cashews so they blend smoothly. To do a quick soak, place the cashews in a small pot. Cover completely with water and bring to a boil. Reduce the heat and simmer for 10 minutes being sure they don't go dry. Drain and blend with 1/2 cup (125 mL) of the broth before adding the cashew cream to the soup to ensure it is perfectly smooth.Instead of Cashews, You Can Use:1 cup (250 mL) canned coconut milk OR 1 cup (250 mL) unsweetened dairy-free milk such as soy or oat. See blog post for more suggestions and tips.No Oven or No Time to Roast the Pumpkin and Garlic?If you don't have an oven, you can substitute the whole head of roasted garlic with 2 cloves of minced garlic, adding it in with the spices and ginger. Peel and chop the pumpkin or squash and add it to the pot with the broth after deglazing. Bring to a boil then reduce to a simmer for about 10 minutes with the lid on, stirring occasionally. You can then blend the soup with an immersion blender or a stand-blender (doing so in batches. Take care not to overfill the blender as the lid can pop off, splattering hot soup everywhere from steam pressure. Return the soup to the pot and simmer it until it reduces and thickens as desired. Pumpkin soup prepared in this manner will be delicious but not as flavorful as one prepared with roasted pumpkin and garlic.