Heat 3 Tbsp. olive oil in your large stock pot or Dutch oven over medium-high heat. Once hot, add the chopped onions and cook for 6–7 minutes until soft and translucent.
Stir in the tomato paste, minced garlic, fennel seeds, and red pepper flakes. Cook for 3 minutes, stirring occasionally, until the tomato paste turns brick-red and starts to caramelize at the edges. This step is where the flavor depth really happens — don't rush it.
Add the cubed heirloom tomatoes and salt. Stir to combine and simmer for 8–10 minutes until the tomatoes start breaking down and releasing their juices. Your kitchen will smell incredible right now.
Carefully transfer the tomato mixture to your blender. Add the silken tofu, ½ cup fresh basil leaves, and ½ cup water. Blend on HIGH for about 1 minute until completely smooth and creamy. With the blender still running, slowly stream in the remaining ¼ cup olive oil. This emulsifies the oil into the soup and gives it that gorgeous, velvety finish.
Pour the blended soup back into the pot and reduce heat to low to keep warm.
Make the Zesty Tomato-Corn Salsa: combine cherry tomatoes, corn kernels, and chopped basil in a medium bowl. Add the red wine vinegar, olive oil, and a pinch of salt. Stir and set aside.
Ladle soup into 5 bowls. Spoon a generous amount of salsa on top of each, finish with a light drizzle of olive oil and cracked black pepper. Serve immediately.
