In a 12" skillet, heat the olive oil over medium-high heat until shimmering. Add onions with a pinch of salt and sauté for 5-7 minutes until browned and translucent. Add the celery, carrots, and garlic and cook, stirring frequently, for an additional 3-5 minutes, until fragrant. Transfer mixture to the slow cooker.
Combine water, beef stock, lentils, ham, smoked paprika, thyme, pepper, and bay leaf. Bring to a boil, then cover. Heat on high for 3 to 4 hours or on low for 6 to 8 hours.
Remove the ham from the slow cooker. Discard the bay leaf and shred the ham. Serve the shredded ham over the top of the lentils, garnish with parsley. Serve immediately.
Preheat oven to 325°. Heat the olive oil in a large 3-quart Dutch oven.
Add onions with a pinch of salt and sauté for 5-7 minutes until browned and translucent. Add the celery, carrots, and garlic and cook, stirring frequently, for an additional 3-5 minutes, until fragrant.
Stir in the water and beef stock. Then add the lentils, ham, smoked paprika, thyme, pepper, and bay leaf. Bring to a boil, then cook, covered, in the oven for an hour to 90 minutes or until the lentils are tender.
Remove the ham from the Dutch oven. Discard the bay leaf and shred the ham. Serve the shredded ham over the top of the lentils, garnish with parsley. Serve immediately.