Heat olive oil in a large heavy-bottom pot over medium-high heat. Add the onion, bell pepper, and celery and cook for 8-10 minutes until the vegetables soften. Add garlic and butter and cook for about 1 minute, or until fragrant.

Add flour and stir to coat the vegetables until no longer visible. Add the broth, potatoes, corn, thyme, bay leaf, smoked paprika, salt and pepper, and bring to a boil. Reduce heat to a simmer and cook uncovered until potatoes are tender and broth has thickened, about 25 minutes, stirring occasionally.

Remove the bay leaf and transfer about 3 cups of the soup and the Greek yogurt to a high-speed blender and process until smooth. Take care when blending hot liquids as they will expand as they mix. You can also use an immersion blender.

Return the pureed soup to the pot and stir to combine. Serve the chowder with green onions and an extra spoonful of Greek yogurt, if desired.