Coat an 8 x 4-inch loaf pan with cooking spray; dust with 4 teaspoons crumbs.
Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, baking soda, nutmeg, and salt in large bowl, stirring with a whisk.
Place butter in a large bowl; beat with a mixer at medium speed until smooth (about 1 minute). Gradually add 1 cup crumbs; beat until well combined (about 2 minutes). Add egg, and beat 1 minute. Add molasses, and beat until well combined.
Beating at low speed, add flour mixture and buttermilk alternately to butter mixture, beginning and ending with flour mixture; beat just until blended. Stir in raisins. Pour batter into prepared pan.
Bake at 350° for 1 hour or until a wooden pick inserted in center comes out clean. Cool in pan 15 minutes on a wire rack; remove from pan. Cool completely on wire rack.