Whisk together flour, baking soda, and salt in a bowl and set aside.
Cream the butter, sugar, and lemon zest in a stand mixer until pale and fluffy.
Mix in the ricotta and vanilla, then add eggs one at a time until incorporated.
Add the flour mixture slowly on low speed until just combined.
Chill the dough in the refrigerator for at least 2 hours.
Preheat oven to 350°F and line baking sheets with parchment paper.
Scoop 1 Tbsp balls of dough and place them 2 inches apart on the sheets.
Bake for 12-14 minutes until the bottoms are golden.
Cool the cookies completely on a wire rack.
Whisk all glaze ingredients together, adding milk slowly until the icing is thick but pourable.
Dip the tops of the cooled cookies into the glaze and add sprinkles if desired.