Melt 2 tbsp butter in a large pot over medium heat. Add 1 diced yellow onion and cook until translucent, about 3 minutes.
Stir in 2 minced garlic cloves, 2 cups diced potatoes, and 1 diced red bell pepper. Cook for 2 minutes.
Sprinkle 2 tbsp flour over the vegetables, stirring constantly for 1 minute to cook off the raw flour taste.
Gradually whisk in 3 cups vegetable broth, ensuring there are no lumps. Bring the mixture to a gentle boil, then reduce heat to a simmer. Cover and let cook for 10 minutes, or until potatoes are tender.
Stir in 1 medium diced zucchini, 1.5 cups corn kernels, 1 cup heavy cream, 1 tsp fresh thyme, 1 tsp salt, and 0.5 tsp black pepper. Simmer uncovered for another 5-7 minutes until all vegetables are tender and the broth is thick and creamy.
Taste and adjust seasoning if necessary. Serve hot with crusty bread.