I am looking for filling/icing for a gingerbread or pumpkin cookie/muffin. Thanks in advance.

I found this:
Autumn Spice
gingerbread cake layered filled with lemon curd
or pumpkin mousse cream cheese frosting
finished in vanilla butter cream icing


PUMPKIN SPICE MOUSSE:
1 1/2 teaspoons unflavored gelatin (less than 1 envelope)
1 1/2 tablespoons cold water
3 large egg yolks
3/4 cup sugar
1 1/2 cups canned solid-pack pumpkin (slightly less than a 15-ounce can)
3/4 teaspoon ground cinnamon
1/4 teaspoon ground ginger
1/8 teaspoon ground cloves
1 1/2 cups well-chilled heavy cream
1 1/2 teaspoons vanilla
18 gingersnaps
In a medium metal bowl sprinkle gelatin over cold water to soften 1 minute. Whisk in yolks and sugar and set bowl over a saucepan of simmering water. Cook egg mixture, whisking constantly, until an instant-read thermometer inserted 2 inches into mixture registers 160°F. (Tilt bowl to facilitate measuring temperature.) Remove bowl from pan and with an electric mixer beat egg mixture until cool and thickened, about 5 minutes (mixture will be very sticky). Beat in pumpkin and spices. Chill pumpkin mixture, covered, until thickened and cool but not set, about 1 hour. In a bowl with cleaned beaters beat cream with vanilla until it just holds stiff peaks and fold into pumpkin mixture gently but thoroughly.

LEMON CURD MOUSSE:
10 large egg yolks
1 1/4 cups sugar
3/4 cup fresh lemon juice
1 stick (1/2 cup) unsalted butter, cut into pieces and softened
1 tablespoon freshly grated lemon zest
1 1/4 cups heavy cream
In a heavy saucepan whisk together the egg yolks and the sugar, whisk in the lemon juice and the butter, and cook the mixture over moderately low heat, whisking constantly, for 5 to 7 minutes, or until it just reaches the boiling point. (Do not let the mixture boil.) Strain the curd through a fine sieve set over a bowl, stir in the zest, and let the mixture cool, its surface covered with plastic wrap. Chill the curd, covered, for at least 4 hours or overnight.

In a bowl with an electric mixer beat the cream until it holds stiff peaks, whisk one fourth of it into the curd to lighten it, and fold in the remaining cream gently but thoroughly.

GOOD LUCK!

Try this link, ladycakes.com has tons of receipes!

http://www.ladycakes.com/Recipes/Fillings/fillings.htm