2 tablespoons olive oil, separated
2 tablespoons unsalted butter, separated
2 pounds portobello mushrooms, in 1/4-inch slices
1/2 carrot, finely diced
1 small yellow onion, finely diced
1 teaspoon fresh thyme leaves (or 1/2 teaspoon dried)
Salt and pepper
3 cloves garlic, minced
1 cup full-bodied red wine
2 cups vegetable broth
2 tablespoons tomato paste
1 cup pearl onions, peeled
1 1/2 tablespoons of cornstarch and 1 1/2 tablespoons water
1 box rigatoni pasta
Heat 1 tablespoon of olive oil and 1 tablespoon of butter in a large dutch oven over a high heat. Once it's starting to sizzle, add the mushrooms and allow to sear on the bottom. Toss and cook until they begin to darken, but not soften, about three to four minutes. Remove them from the pan.
Reduce the heat to medium and add the remaining olive oil. Add the carrots, onions, thyme, salt and pepper. Saute about 10 minutes.
Add the garlic, and cook one additional minute.
Add the vine, scrape the fond off the bottom of the pot, and then turn the heat up to high and reduce the sauce by half. Add the broth and tomato paste.
Stir well and add the mushrooms back, along with any juices they've expelled. Bring the mixture to a boil, and reduce the heat to medium.
Simmer 20 minutes. Add the pearl onions, and simmer five to 10 minutes.
Make cornstarch slurry, add it to the pot and stir well. Simmer 10 to 15 minutes.
While the sauce simmers for its final 10 to 15 minutes, cook the rigatoni according to the instructions on the box. Drain.
Serve the sauce over the pasta, or stirred in, according to your preference.
