Add the squash, onion, broth, and avocado oil to a medium pot. Bring to a boil over medium-high heat.
Reduce the heat to maintain a simmer, cover, and cook until the squash is tender, about 10 minutes.
Remove from the heat and add the cream cheese. Allow to cool slightly.
Using an immersion blender, blend the mixture until smooth (or let cool and blend in a regular blender in batches). Stir in salt and black pepper to taste.
Notes
Cut the yellow squash into uniform pieces so they cook at the same rate and blend smoothly.Before adding broth, sauté the squash with onion and garlic in a bit of butter or oil to deepen the flavor.Let the squash simmer until it’s fork-tender. This makes blending easier and helps create a smoother texture.Use an immersion blender for fewer dishes, or a countertop blender for ultra-smooth results. Blend in batches if needed.If the soup is too thick, stir in more warm broth or a splash of milk to loosen it up without watering it down.Top with croutons, chopped herbs, or a swirl of cream for added texture and contrast.