Yields Makes about 36 cookies
Prep and Cook Time: about 1 1/2 hours. Notes: Oatmeal gives these jam-filled cookies a hearty texture. Store the cookies airtight for up to 2 days.

How to Make It

Step 1
1

In a bowl, with an electric mixer on high speed, beat butter, brown sugar, egg yolk, and vanilla until smooth. Stir or beat in flour and oats until well blended.

Step 2
2

In a small bowl, beat egg white and 2 teaspoons water to blend. Put walnuts in a shallow bowl. Shape dough into 2-teaspoon-size balls and dip in egg white mixture; shake off excess, then roll in walnuts. Place 1 inch apart on buttered or cooking parchment-lined 12- by 15-inch baking sheets. Press your thumb into the center of each cookie to make a 1/2-inch-deep indentation.

Step 3
3

Bake cookies in a 300° oven until lightly browned, about 15 minutes; if baking more than one pan at a time, switch pan positions halfway through baking.

Step 4
4

Carefully fill each indentation with about 1 teaspoon jam (if indentations have disappeared, make them again with the rounded end of a wooden spoon). Return to oven and bake until cookies are golden brown and jam has melted, about 15 minutes longer. With a wide spatula, transfer cookies to racks to cool completely.

Step 5
5

Note: Nutritional analysis is per cookie.

Ingredients

 1 cup (1/2 lb.) butter, at room temperature
 1/2 cup firmly packed brown sugar
 1 large egg, separated
 1 1/2 teaspoons vanilla
 1 cup all-purpose flour
 2 cups rolled oats
 1 1/2 cups finely chopped walnuts
  About 1 cup fruit jam

Directions

Step 1
1

In a bowl, with an electric mixer on high speed, beat butter, brown sugar, egg yolk, and vanilla until smooth. Stir or beat in flour and oats until well blended.

Step 2
2

In a small bowl, beat egg white and 2 teaspoons water to blend. Put walnuts in a shallow bowl. Shape dough into 2-teaspoon-size balls and dip in egg white mixture; shake off excess, then roll in walnuts. Place 1 inch apart on buttered or cooking parchment-lined 12- by 15-inch baking sheets. Press your thumb into the center of each cookie to make a 1/2-inch-deep indentation.

Step 3
3

Bake cookies in a 300° oven until lightly browned, about 15 minutes; if baking more than one pan at a time, switch pan positions halfway through baking.

Step 4
4

Carefully fill each indentation with about 1 teaspoon jam (if indentations have disappeared, make them again with the rounded end of a wooden spoon). Return to oven and bake until cookies are golden brown and jam has melted, about 15 minutes longer. With a wide spatula, transfer cookies to racks to cool completely.

Step 5
5

Note: Nutritional analysis is per cookie.

Oatmeal Thumbprints

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