Rinse and drain the lentils and set aside.
Cook the bacon in a large soup pot or Dutch oven until crisp. Transfer the bacon to a paper towel lined plate. Once cool, crumble and set aside for topping.
Drain most of the bacon grease, leaving about 2 tablespoons in the pot.
Add the celery, carrots, and onion. Cook for 10 to 15 minutes until softened. This step helps the carrots become tender before the lentils finish cooking.
Stir in the potatoes, lentils, and the seasoning packet from the lentil package.
Pour in the chicken broth. Bring to a boil, then reduce heat and simmer for 30 to 35 minutes, stirring occasionally, until the lentils and potatoes are tender and the chowder has thickened.
Remove from heat. Stir in the smoked Gouda and heavy cream until melted and smooth.
Add the lemon zest. Taste and season with salt and pepper as needed.
Serve topped with the crumbled bacon, parsley, and extra Gouda if desired.