Preheat the oven to 425F and line a large baking sheet with parchment paper.
Make the dressing: In a small mixing bowl whisk together the tahini, mustard, maple syrup, lemon juice, pressed garlic clove, kosher salt and black pepper. Once combined, add 3 tbsp cold water and whisk until it becomes a creamy, smooth dressing. If desired, add an additional 1 tbsp cold water and whisk again.
In a large bowl combine lentils, the chopped sweet potatoes, halved or quartered brussels sprouts and chopped red onion. Add olive oil, salt, pepper and fresh minced rosemary. Toss everything together in the bowl and make sure everything is well-coated.
Add the lentil mixture from the large bowl onto the parchment paper lined baking sheet and spread out into an even layer.
Roast for 20 minutes, tossing everything on the pan at the 20 minute mark. Put back in the oven and roast for 10 more minutes. Remove from the oven.
Serve the salad in a large serving bowl or on a serving platter and add the chopped dates and pumpkin seeds. Drizzle the dressing over, toss and then enjoy! Alternatively, you can add the chopped dates and pumpkin seeds directly to the sheet pan, drizzle with the dressing and serve right from the sheet pan onto plate.
Notes
Make sure you use as large a sheet pan as possible so everything roasts thoroughly. I use a sheet pan that is 21 inches by 15 inches
If you don't have sweet potatoes, you can swap for butternut squash or even carrots.
Broccoli can be swapped in for brussels sprouts if thats more of your preference.
You can also top this salad with your favourite protein or serve with a protein like roast chicken.
Red onions can be swapped for chopped shallots if you desire or if that's all you have on hand.
If you don't have fresh rosemary on hand, swap for 1 tsp dried rosemary.