My love of gluing things together blossomed when I was very young.
In kindergarten, I spent many late nights working feverishly at my Little Tikes kitchen with scissors, glue, and whatever material I could get my tiny hands on. To my parent's dismay, every cut-able item within reach became a potential craft supply. They frantically hid anything of value while I went to town on catalogs, cardboard boxes, socks missing their mates, and whatever else I could find. I'm all grown up now, but nothing has changed.
Slicing apart the junk mail to make tiny doll house sized food was one of my favorite past times (along with mixing condiments together from the fridge, using bobby pins to pick locks, and drawing on my bedroom walls). Again...nothing has changed. The food I made never looked this nice because I didn't have colored permanent markers, an x-acto knife, or very good motor skills at the time.
You will need:
junk mail with pictures of food in it
foam core board
colored permanent markers
In the ads, find images of boxed food.
Look for boxes of chocolate, cereal, cookies, pizzas, and anything else that comes in a flat box. Leaving a little excess paper around the edges, cut the images out and glue them to the foam core board. Corrugated cardboard may be used in place of the foam core. Its easier to cut, but your boxes will not have the clean, flat edges to work with (as a kid, I never cared about that).
To cut them out, I recommend using an x-acto knife and a metal ruler. Place the ruler over the food image and cut around it. Because the paper can snag and tear, you'll want the image protected under the ruler as you cut. Sadly, I learned this lesson the hard way by tearing a very promising little package of Oreos.
With your colored permanent markers, carefully color the sides of your box to match the front. Beware of coloring near the edges of the image, the ink can bleed into the paper.
If your doll house has a cleaning supply closet, the food images could be swapped for boxed laundry detergent, dryer sheets, Kleenex, or packs of paper towels.