Cut the top quarter off the head of garlic and drizzle with ½ tablespoon olive oil. Wrap it in foil and set it in a small oven-proof dish. Bake it for 20 minutes. Remove it from the oven and keep it wrapped to cool. It will continue to cook as it cools.
Turn the oven up to 425 degrees.
While the garlic roasts bring a pot of water to a boil. Blanch the carrots in the boiling water for 2 minutes. Then add the beets and boil for 8 to 10 minutes. Remove them with a slotted spoon and run under cold water. At this point, the skins should easily peel off the beets by using your finger. Use a peeler if needed for tougher skins.
Halve the carrots and quarter the beets. Arrange them on a baking sheet. Drizzle with 1 tablespoon olive oil and sprinkle with salt. Roast for 20 minutes, flipping vegetables halfway through.
Arrange the chard on another baking sheet. Drizzle with ½ tablespoon oil and pinch of salt, and rub it all over the leaves. Roast for 5 minutes, or just until the leaves have softened and become slightly browned.
Next make the dressing. Squeeze the roasted garlic out of its papery skin and into a small mixing bowl. Mix in lemon juice and add a pinch of salt. Next, whisk in the remaining 3 tablespoons olive oil and combine until smooth.
Lastly, toast the pepitas in a small skillet over medium heat. Cook, while flipping almost constantly for 2 minutes or until they start to pop. Sprinkle with salt.
To serve, toss the carrots and beets with the garlic dressing. On a large platter, layer roasted chard on the bottom, then the carrots and beets, a drizzle more of garlic dressing then sprinkle on the pepitas, black pepper and more salt if desired.