Heat the olive oil in a large frying pan.
Add the shredded carrots, red onion, kosher salt, and freshly ground black pepper. Cook, stirring occasionally until the vegetables are soft.
Remove to a large bowl and set aside.
Return the pan to the heat, add half of the baby spinach, and sprinkle with salt. Cook, stirring occasionally until the spinach is wilted.
Add the remaining spinach and cook until all the spinach is wilted.
Remove the spinach to a colander in the sink. Press on the spinach to remove liquid.
Once cool enough, use clean hands to squeeze out as much liquid as possible.
Use layers of paper towels to again squeeze any residual moisture out of the spinach.
Remove the paper towels, finely chop the spinach, and add to the bowl with the vegetables.
Add the sour cream, mayonnaise, Worcestershire sauce, and freshly squeezed lemon juice and stir to combine.
Cover the bowl with plastic wrap and chill the dip for 2 hours or longer before serving.