Preheat the oven to 425 degrees F. Line a baking sheet with parchment paper.
Arrange the tomatoes on a cutting board and sprinkle with salt. Let sit 15 minutes to draw out excess moisture.
Meanwhile, make the ranch seasoning. Combine all ingredients in a bowl.
Lay the thawed puff pastry on the prepared baking sheet and prick all over with a fork.
Spread the crème fraîche over the dough, leaving a ¼-inch border.
Top with cheddar cheese.
Layer on the tomatoes, then sprinkle the ranch seasoning over each tomato.
Transfer to the oven and bake for 25-30 minutes or until the pastry is golden and the cheese melted.
Serve warm or at room temperature with a dollop of crème fraîche, yogurt, or sour cream, and fresh basil.
