Start by shucking the fresh corn off the cobs, ensuring to get all the sweet kernels. Chop the yellow potato, carrot, zucchini, and onion into small, bite-sized pieces. Set aside.

In a large pot over medium heat, melt 2 tablespoons of butter until bubbly. Add the chopped onion and sauté for 2-3 minutes until translucent.

Stir in ¼ cup of flour with the softened onions, combining for about 1 minute to form a roux.

Gradually whisk in 4 cups of vegetable broth, stirring continuously. Add the corn, diced potato, and carrot. Bring to a gentle boil for 2-3 minutes.

Reduce heat to medium and let chowder simmer uncovered for 15 minutes, stirring occasionally.

Add the chopped zucchini and fresh spinach to the pot, stir, and pour in 1 cup of milk. Simmer for an additional 5-10 minutes.

Season your chowder with salt, pepper, and 1 teaspoon of fresh thyme. Stir well and serve hot.