In the bowl of a stand mixer with paddle attachment or in a large bowl with a hand mixer (or with a large mixing bowl and silicone spatula or wooden spoon), cream butter and brown sugar on medium speed until light and fluffy, 3-4 minutes.
Add vanilla and blend until combined.
Add flour to mixture, along with ground ginger, cinnamon, cloves, nutmeg, and salt and blend until just combined. Keep mixer on low and add molasses and 4 tablespoon milk in until dough comes together. If cookie dough seems too thick, you can add an additional tablespoon of milk.
Mix in sprinkles, if desired.