Preheat oven to 325F. In bowl, beat butter and sugar together until creamy and smooth. Add eggs and beat well. Stir together flour, baking soda and salt, and then add. Mix until combined. Stir in pumpkin butter, vanilla extract, lemon juice and pecans. Fill buttered muffin pans 3/4 full (or use muffin liners). Bake until toothpick inserted in center comes out clean, about 25 - 30 minutes. Remove muffins from pan and cool on wire rack.