Line an 8 x 8-inch pan with foil and coat with nonstick spray. Set aside.
In a 3-quart saucepan combine almond paste and sweetened condensed milk. Heat over medium-low heat until almond paste is melted. Add white baking pieces; heat and stir until melted. Remove from heat. Add a few drops of blue food coloring gel. Use a spatula or knife to swirl.
Pour half of white chocolate mixture into prepared pan. Top with marshmallows and almonds. Pour remaining mixture over marshmallow layer. Top with sprinkles. Refrigerate 2 hours to set. Use foil to lift out of pan; peel foil away from fudge and transfer to a cutting board. Cut into squares or triangles.