With a stand mixer (use the paddle attachment) or a hand mixer, beat the butter and ricotta on medium-high speed until light and fluffy, about 2 minutes. Add the sugar, orange zest, and vanilla; beat until blended, about 3 minutes. Scrape the bowl. On medium speed, add the egg and beat until blended. Add the flour mixture and mix on low speed until almost completely blended. Pour in the chocolate
chips and continue mixing until just incorporated. Scrape the dough down from the sides of the bowl, cover with plastic, and refrigerate until slightly firmer, about half an hour.