Fans of delayed gratification, Shake Shack frozen custard drinks and helping hungry kids are having a good month: A donation of $2 to a charity called Share Our Strength gets a card good for a free shake on the next visit to the Harvard Square burger joint.

This is the third annual monthlong Great American Shake Sale for the fast-food chain. Publicist Nina Travers says the first sale raised $135,742, last year’s raised $285,862 and the current goal is up to $300,000, the equivalent of giving away 150,000 shakes.

The money goes to a Share Our Strength campaign called No Kid Hungry that aims to connect some of the nation’s 16 million food-insecure children – that’s one in five – with healthy food and nutrition programs.

What donators get in return is more delicious than healthy, of course. The seven shake flavors on the “custard calendar” are inspired by baked goods: Caramel Praline Cake; Lemon Meringue; Buttery Sugar Cookie; Oatmeal Crème Pie; Banana Bread; Chocolate Cheesecake; and Black & White Cookie.

Shake Shack is open daily from 11 a.m. to 11 p.m. at 92 Winthrop St., Harvard Square.

This post was written from a press release.