This is probably the one you are looking for.And it does come from a Betty Crocker check out cookbook. Mine is dated April 2005, but I'm sure it's the same one.

Strawberry Daquiri Cake

Cake:
1 pkg. Betty Crocker SuperMoist white cake mix
3/4 c. water
1 pkg strawberry flavored unsweetened drink mix
1 Tbsp. grated lime peel
3/4 tsp. rum extract
1 pkg. (10 oz) frozen sliced strawberries, thawed, undrained
3 eggs

Lime Frosting:
1 tub (15 oz) Betty Crocker Pour & Frost vanilla frosting
2 tsp. grated lime peel

Garnish:
8 fresh whole strawberries

Heat oven to 350'. Grease bottom only of 13x9 inch pan with shortening or spray bottom with cooking spray.

In large bowl, beat cake mix, water, drink mix (dry), 1 Tbsp lime peel, rum extract, thawed strawberries and eggs with electric mixer on low speed for 30 seconds. Beat on medium speed for two minutes, scraping bowl occasionally. Pour into pan. Bake 30 to 35 minutes or until toothpick inserted in center comes out clean. Cool completely, about 1 hour.

Uncover tub of frosting and remove foil. Microwave frosting on high 20-30 seconds or until pourable. Stir in 2 tsp. lime peel. Pour frosting over cake; spread evenly. Store loosely covered at room temperature. Just before serving, cut whole straberries in half, leaving leaves on. Garnish cake with strawberry halves.

This is just how it appears in the book. You could use real rum in place of the extract. Hope this is it!