Blend the chipotles with 1 cup of broth on high speed until mostly smooth, about 30 seconds. Set aside.
1/4 cup canned chipotle peppers in adobo sauce, 2 cups vegetable broth, divided
In a large skillet, heat olive oil over medium-high heat. Once the oil is hot, add in the garlic, followed by the peppers and onions. Cook, stirring occasionally, until the vegetables begin to soften but are still crisp, about 3-5 minutes.
3 tbsp olive oil, 2 cloves garlic, finely chopped (about 1 tbsp), 1 large red bell pepper, diced (about 1 cup), 1 large green bell pepper diced (about 1 cup), 1/2 medium red onion, diced (about 1 cup)
Add in the butter and allow it to melt. Sprinkle the flour over top of the butter and vegetables. Stir to mix the flour into the butter and create a paste, about 1 minute.
4 tbsp unsalted butter, 2 tbsp flour
Add in the blended chipotles, remaining broth, and heavy cream. Stir to blend everything together. Allow the sauce to simmer (adjust the heat as necessary) and reduce in volume. The sauce should thicken and become creamy, about 10 minutes.
1 cup heavy whipping cream, 2 cups vegetable broth, divided
Once the sauce is to your desired consistency, adjust for salt and stir in about half of the cilantro. Add in the cooked pasta and mix all of the ingredients to evenly coat the pasta and warm everything through.
1 lb penne pasta, cooked al dente per package directions, salt to taste, 1 cup chopped cilantro, divided
Top with the remaining cilantro and serve warm.
1 cup chopped cilantro, divided