Step 1

Put the carrots and celery in a 6- to 8-quart slow cooker. Top with the chicken; sprinkle with the garlic, red pepper flakes, ½ teaspoon salt and a few grinds of pepper. Whisk the broth with the flour in a medium bowl until smooth; pour over the chicken. Cover and cook on low, 7 hours.

Step 2

About 20 minutes before serving, bring a medium pot of salted water to a boil. Add the pierogi and cook as the label directs. Drain.

Step 3

Uncover the slow cooker and stir, breaking up the chicken. Add the pierogi, peas and heavy cream and stir. Let stand, uncovered, 10 minutes. Stir in the dill; season with salt and pepper.