In a small bowl, combine flour, baking powder and salt. In a large saucepan, melt butter and chocolate over low heat, stirring until smooth. With a wooden spoon, beat in 1 1/2 cups of sugar. Add 4 eggs and 2 teaspoons of vanilla, beat until well blended. Stir in flour mixture just until blended.
In a small bowl, with mixer at medium speed, beat cream cheese until smooth, gradually beat in remaining sugar. Beat in remaining egg, almond extract and vanilla until just blended.
Spread 1/2 of the chocolate batter in prepared pan. Spoon creamcheese mixture in large dollops on top of chocolate. Spread remaining chocolate batter over cream cheese mixture. "Marble" with a butter knife by swirling the knife in broad strokes.
Bake until a toothpick inserted in the center comes out almost clean, about 35-40 minutes.