Grease a rectangular pyrex (or rectangular baking pan) and preheat oven to 350 F
On medium speed, cream butter and sugar until smooth. Add eggs, one at a time, beating well after each addition. Add vanilla and lemon essences. Add the flour and mix thoroughly.
Spread batter evenly into pyrex and with a knife score squares as shown. Place a teaspoon of pie filling in the center and bake for 30 - 35 minutes, or until a cake tester inserted in the center of the pan comes out clean. Cool to room temperature, then slice into squares.