Mocha Macaroon Tart

For Crust:

Preheat oven to 350 degrees. Line a 9 inch tart pan with removable bottom with foil. Brush foil with oil. Combine almonds, sugar, flour and coffee powder in a food processor. Process until finely ground. Add egg white and vanilla and blend until dough almost forms a ball. Press into bottom of prepared pan with wet fingertips. Bake about 14 minutes until crust is dry and firmed. Cool.

For Dark Chocolate Filling:

Combine cream. butter, corn syrup and coffee powder in a medium saucepan. Bring to a simmer, stirring occasionally. Add chocolate and whisk until smooth.

For White Chocolate Filling:

Combine cream, corn syrup and coffee powder in a large saucepan. Heat to a simmer. Add chocolate and stir until smooth. Whisk in sour cream.

Drop chocolate filling alternately with white chocolate filling by the 1/4 cupful onto cooled crust. Swirl together with the tip of a knife. Freeze 1 hour. Remove tart from pan. Invert and peel off foil. Let stand 30 minutes at room temperature. Cut into wedges and serve with whipped cream if desired.