。
Beat the eggs well.
Literal
Egg [object-を] well beat-mix.
かき混ぜる is a compound verb: かき (prefix from 掻く 'to scratch/stir') + 混ぜる ('to mix'). The かき prefix is a common intensifier for stirring/mixing actions. Dictionary form used as a polite-register command — an instruction tone typical of recipes.