In a large bowl, mix butter and sugar with mixer until light & fluffy, about 5 minutes. Stir in the eggs, one at a time, blending well with each egg. Stir in vanilla and flour just until mixed. Spoon batter into cups, dividing evenly.
Bake until tops spring back when lightly pressed, 18 to 20 minutes. Cool in pan over wire rack. Put on serving plate when cool.
Use bright blue paste food coloring for fur, added into vanilla frosting (bought or homemade). Use sanding sugar over top of frosting and leave a slit for a 1/2 of mini chocolate chip cookie for his mouth, 1/2 of mini marshmallow for eyes, or a thin white round candy for the whites of the eyes and a mini chocolate chip for pupils.