Every Friday morning, 12 3- and 4-year-olds in Alicia Troncoso's class at Annandale Cooperative Preschool begin their day baking three dozen muffins.

The treats are not for themselves. Instead, the parent-run coeducational cooperative school sends the muffins to the Baileys Crossroads Community Shelter in Falls Church where as many as 40 people will come that day for lunch.

Troncoso, of Annandale, and her 21-year-old daughter, Andrea, an early childhood education student at George Mason University, help the children wrap the muffins and sign a homemade card. A parent delivers the package to the shelter.

The idea for the service project occurred to Troncoso when a batch of cupcakes intended for a child's birthday was accidentally collected from the kitchen of Little River United Church of Christ and delivered to a church-sponsored charity project. Annandale Cooperative Preschool rents space from, but is not affiliated with, the church.

Troncoso, who also volunteers with Project Success, a Fairfax County service-learning project that brings together teenagers with and without disabilities, saw the "missing cupcakes" as an opportunity to use what she had learned working with the teenagers. She said she wanted to "plant a seed in the hearts and minds of the children."

"I couldn't tell them that the cupcakes went to a homeless shelter," Troncoso said. "It would have been meaningless to a 3-year-old. Instead, I said they went to a place where people didn't have enough to eat and don't have a house to live in."

Troncoso did not get to tell the whole story. Christine Rubeiz, whose mother had baked the cupcakes for the girl's birthday, wanted to tell her friends what happened.

"Christine was happy about it," said her mother, Karen Rubeiz of Fairfax, "and Alicia was able to explain in a way that was age-appropriate that this was something special that we could do for these people."

"I saw their faces," added Troncoso, "and I said, 'I want to do something with this.' So I asked the children, 'What else can we send?' "

The ideas ranged from pizza to cookies, but the children settled on a weekly project of baking muffins.

Troncoso models the service-learning project on the county's Project Success curriculum. "It's called PARC," she said. "It stands for plan, act, reflection and celebration. So it's not just baking muffins."

She added: "We do problem-solving, which is math; measuring, which is science; and writing the card, which is English. We have a civics lesson, too. We vote on what kind of muffins we'll make."

On a recent week, apple cinnamon muffins won the vote. A parent donates the muffin mix on a rotating basis.

"It's a small school so you can smell them everywhere when they're baking," said Andrea Troncoso, who supervises the project. Annandale Cooperative Preschool, founded in 1947, is for children ages 2 to 4.

Muffin making is a low-key, low-tech affair that begins as the children arrive, in stages, in the morning.

"Wash your hands," Andrea said to several children who came by to help. "Who is going to help me carry the muffins to the kitchen?" She appealed to one of the boys. "R.J.? I need some muscles."

When they finished mixing the muffins and spooning them into baking cups, it was the girls who brought them down the hall to the industrial kitchen. Jessica Bethke, Kate Meldrum and Amelia Gulding, all 3-year-olds, carried two trays between the three of them.

"I want to make this meaningful for the students," Alicia Troncoso said. "Some kids learn in different ways, so we try to involve everybody according to their interest. It's something I picked up from Project Success."

There is a photo album in the classroom, a parent project, called "We Care." The cover features a heart made of cupcake stickers -- because cupcakes were the impetus for the project -- and inside are photos of other Friday morning baking sessions.

The weekly project has had an impact on the children beyond the classroom, according to Maria Meldrum of Vienna, mother of 3-year-old Kate Meldrum.

"The day Kate and I were going to take the muffins to the shelter, she was crying and didn't want me to take them," she said. "I hadn't explained to her what we were going to do. So I said she could stay in the car if she didn't want to come inside. But I made it sound important and I told her 'people might be sad if we don't bring the muffins.' "

"Then she stopped crying," Meldrum added, "and she said, 'I'll go with you. I don't want anyone to cry because they are hungry.' "

Meldrum said she never thought to involve a 3-year-old in a service project. She has since involved her children in another home-based initiative: donating toys.

"I wanted this to be different," she said. "I could have picked out toys I knew my children no longer used, but I wanted them to choose what they donated. I told Kate that maybe the people we feed have children and they don't have toys. So she went upstairs and got a teddy bear she loved. She said, 'Maybe someone will want to hug this' and put it into the donation box.

"They're more capable of giving and caring than you can imagine," Meldrum added.

Alonzo Davis, director of the Baileys Crossroads Community Shelter, agreed. "I think they're an inspiration to the residents of the shelter," he said. "Many of our clients have children of their own. Seeing what these children do allows them to reconnect to their own families and fills a missing piece in their life.

"I think that gives them hope."

Four-year-olds Matt Gutermuth, above left, and Michael Richardson prepare a muffin tray while Kate Meldrum, 3, mixes batter at Annandale Cooperative Preschool, where adults help students bake three dozen muffins on Fridays for a homeless shelter. Andrea Troncoso, who volunteers at the Annandale Cooperative Preschool where her mother teaches, helps Aubrey Broxson, 3, make muffins for the Baileys Crossroads Community Shelter.