Step 1

Heat grill to medium-high; lightly oil grates. In a large bowl, toss tomatoes with 1 tablespoon oil; season generously with salt and pepper. Arrange tomatoes on grill, cut sides down first. Cover and grill until soft and charred, 5 to 10 minutes per side. With a metal spatula, return tomatoes to bowl. When cool enough to handle, use kitchen shears to snip tomatoes into smaller pieces.

Step 2

To tomatoes, add garlic, vinegar, and red-pepper flakes; season with more salt and pepper.

Step 3

Reduce heat to medium. Brush bread with remaining oil; grill on both sides until beginning to char, about 2 minutes per side. Cut bread slices in half; divide tomato mixture evenly over each. Top with basil and serve.