After more than 100 years in business, a beloved bakery on the Upper East Side will close its doors this weekend.

Glaser's Bake Shop, on First Avenue between 87th and 88th Streets, will close on Sunday.

The same family has owned the bakery for 116 years.

Glaser's is known for its black and white cookies which the owners say were created by the original matriarch of the family.

Customers with fond memories at the bakery are having a tough time letting go.

"I love this bakery and I'm definitely really sad that it's closing. I used to do Girl Scouts right across the street and I used to come here every day to get the best black and white cookies in the world," said one customer.

"It's all about the black and whites. I moved up here about five years ago, stumbled onto it one day and it was the greatest cookie I ever had. They've kind of hated me - I asked for two dozen before and it took a heck of a long time for them to actually pack up. So I'm just trying to get my fix in before they close," said another customer.

Loyal customers have been lining up around the block since they got the news about the bakery's closing.