Adapted from Jeanine Franson, my mother-in-law's, recipe.
In medium bowl, sift:
3 c. flour (spoon lightly into cup to measure)
1 t. baking powder
1/2 t. salt
In large bowl, or in stand mixer, beat till light and fluffy:
2 sticks butter
1/2 c. shortening
2 2/3 c. sugar
Then add and mix until just blended:
1 c. milk
3 T. pure lemon extract
Then add dry ingredients and mix until just combined.
Scrape bottom and sides of bowl several times in the process.
5 eggs, one at a time, beating until completely blended, but not whipping.
Butter the bottom and sides of a 9 x 13" pan at least 2" deep. Pour in batter and bake at 320 degrees about 1 hour 15 minutes, until light golden brown and toothpick or knife inserted in center comes out clean. Check for doneness after 1 hour, or as soon as you smell the goodness of the cake and see that it is beginning to brown.
While cake is baking, prepare a mixture of 6 ounces of lemonade concentrate and 3/4 cups sugar. (I like to 1 1/2 times this) Microwave for a minute and mix well till thoroughly dissolved.
As soon as cake is out of oven, run a knife around sides of pan and prick top all over with a fork (a meat fork if you have one). Pour lemonade mixture over hot cake and spread to cover completely, including sides. Let it soak in completely; then sprinkle sugar lightly over top. For a crunchy texture, sprinkle again before serving.
Ages well; freezes well.