Seared fennel & tomatoes with mustard vinaigrette

Mustard, Dijon	2 tablespoons
Vinegar, red wine	2 tablespoons
Oil, extra-virgin olive	½ cup + 6 tablespoons
Salt, kosher
Pepper, freshly ground
Tomatoes, Roma, halved lengthwise	4
Fennel bulbs, trimmed, sliced ½-inch-thick lengthwise through the core; small fronds reserved for garnish	3
Basil leaves	Garnish

1. In a small bowl, whisk the mustard with the vinegar. 
2. While whisking constantly, drizzle in the ½-cup oil until emulsified; season with salt and pepper. 
3. Heat a griddle or large skillet. (Note: Avoid cast-iron as the tomato juice acid is rough on the pan.) 
4. Brush the tomatoes and fennel all over with the remaining 6-tablespoons oil; season with salt and pepper. 
5. Working in batches, cook the tomatoes cut side down until lightly charred, about 3 minutes; transfer to a platter charred side up. 
6. Working in batches, cook the fennel, turning once, until just tender and lightly charred, about 6 minutes; transfer to the platter with the tomatoes. 
7. Drizzle the vegetables with the vinaigrette, and garnish with the reserved fennel fronds and basil leaves. 
8. Serve warm or at room temperature. 

Recipe mildly adapted from Food&Wine Magazine, September 2017.