Good things come in small packages: taxidermied rodents, pills, our diamonds.

With today’s noon rollout of Brown Betty Petite, the truism is proven again.

That’s when the No Libs boutique bakery opens a Rittenhouse outpost that sells only their slobber-inducing cupcakes.

The space is minimal: one fridge for cuppies-to-go, one rack for room-temp treats to cram in your piehole immediately. And it’s tiny, all brown and pink with vintage touches like the owners’ family photos.

Certain flavors will be sold on certain days (Carrot Patch on Tuesday, Thursday, and Saturday); new additions like Sally’s Fruit-Filled Pound Cake top our must-try list; and the signature coconut-crusted layer cake (Company’s Comin’) is available as, you guessed it, a cupcake.

Do we really have to say it again?

Brown Betty Petite, 269 South 20th Street (215-545-0444 or brownbettydesserts.com).