Preheat oven to 350°F.
Butter and flour 2 8-inch layer cake pans.
In a large bowl, beat butter until fluffy.
Beat in honey, then egg yolks, water, and vanilla.
Gradually add cake mix, beating for 4 minutes.
In a medium-size bowl, beat together egg whites and cream of tartar until whites are stiff.
Fold into batter.
Turn into prepared pans, and bake on middle shelf of oven for 30 to 35 minutes, or until a cake tester or food pick inserted into the centers comes out clean.
Cool in pans for 10 minutes.
Turn out onto wire racks to cool completely.
Preparation time (not including baking): 10 minutes