Butter Lettuce Salad with Tomato Vinaigrette

1. 2 plum tomatoes, halved
2. 2 medium shallots, quartered lengthwise
3. 1/3 cup canola oil, plus more for brushing
4. 1 tablespoon plus 2 teaspoons sherry vinegar
5. 2 teaspoons Dijon mustard
6. 2/3 cup crumbled blue cheese (2 1/2 ounces)
7. 1/3 cup plus 1 tablespoon extra-virgin olive oil
8. Kosher salt
9. Freshly ground pepper
10. 1/2 cup pumpkin seeds
11. 1 1/2 teaspoons pure chile powder, preferably guajillo
12. 1/4 pound slab bacon, cut into 1/4-inch dice
13. 2 medium heads butter lettuce, quartered through the cores
14. Thinly sliced onion and diced tomato, for serving

1. Preheat the oven to 425º. Brush the tomatoes and shallots with canola oil. Roast on a rimmed baking sheet for about 30 minutes, until softened and browned in spots. Transfer to a blender and let cool completely. Add the vinegar and mustard and puree until nearly smooth. Add the blue cheese and puree until smooth. With the machine on, gradually add the 1/3 cup of canola oil and 1/3 cup of olive oil until incorporated. Season the vinaigrette with salt and pepper.
2. In a pie plate, toss the pumpkin seeds with the remaining 1 tablespoon of olive oil and the chile powder and season with salt and pepper. Bake for about 10 minutes, until lightly browned; let cool.
3. In a skillet, cook the bacon over moderate heat, stirring, until browned and crisp, about 7 minutes. Transfer to paper towels to drain.
4. Arrange the lettuce wedges on plates and top with the pumpkin seeds, bacon, sliced onion and diced tomato. Serve with the tomato vinaigrette.