Place poblano peppers on a cookie sheet. Drizzle with 1 tbsp. olive oil. Toss to evenly coat. Bake for 20 minutes or until the pepper skin forms blisters and the peppers begin to deflate. Peel the skin from the peppers and remove the seeds.
Place peppers, 1/3 cup olive oil, ½ cup pecan halves, garlic, cheese, salt and pepper in the bowl of a food processor. Process until smooth.
Meanwhile, cook pasta according to package directions, reserving ¼ cup of pasta cooking liquid before draining. Coarsely chop remaining ¼ cup pecan halves. Toss pesto with cooked pasta and chopped pecans. Thin with reserved ¼ cup cooking liquid, if desired.