Warm the olive oil in a medium-sized saucepan set over medium heat. Once the oil shimmers, add the chopped sweet onion and sauté, stirring often, until softened and translucent—this should take about 3 to 5 minutes.

Introduce the diced potato, fresh thyme sprigs, bay leaf, and minced garlic to the pan. Season with about 1/2 teaspoon kosher salt and a few turns of freshly cracked black pepper. Stir everything together, ensuring the potatoes are evenly coated in the fragrant mixture. Continue cooking for another 2 to 3 minutes.

Pour in the chicken broth along with 1 cup of water. Bring the mixture to a gentle simmer. Stir in the frozen corn and chopped fennel, and allow the soup to simmer uncovered for around 20 minutes, or until the vegetables are tender when pierced with a fork. Adjust the heat as necessary to maintain a consistent simmer without boiling.

Remove the pot from the heat and let it cool slightly—about 5 minutes. Discard the thyme sprigs and bay leaf. Blend the soup in batches using a standard blender (fill no more than halfway and leave one corner of the lid open, covered with a towel to prevent splashes) or use an immersion blender directly in the pot to achieve a smooth consistency.

Stir in the heavy cream, starting with 1/4 cup and increasing to 1/2 cup if you prefer a richer texture. Gently reheat the soup over low heat if needed. Adjust the consistency with a splash of water and fine-tune the seasoning with additional salt and pepper.

Ladle the hot soup into bowls and garnish with a handful of thawed corn kernels and delicate fennel fronds for a fresh, vibrant finish.