Mix yeast and warm water until dissolved.
Combine cake mix, salt and flour in a large bowl.
Add warm water/yeast mixture and vanilla to cake mix, salt and flour mixture. Mix well. This may require kneading with your hands a bit to completely combine ingredients.
Cover tightly. Let rise for one hour. Punch down and let rise again for another 30-60 minutes.
Divide dough in half. On a floured surface, roll one half of dough into a rectangle shape, approx 1/4? thick.
Once dough is rolled out, brush with half of softened butter.
Combine white sugar, lemon zest and JELL-O Lemon Flavor Instant Pudding Mix in a bowl, stirring until well combined.
Sprinkle half of the sugar, lemon zest and JELL-O Lemon Flavor Instant Pudding mix over buttered dough.
Starting at end opposite from you, roll the dough towards you until all dough is rolled into one long piece.
Slice dough into 12 equal sized pieces. Place 12 rolls into a 13x9 inch pan that has been sprayed with non stick cooking oil.
Repeat process with remaining dough to make the second pan of lemon rolls.
Cover and let both pans rise until almost doubled in size, approximately 30 minutes. Don't worry if rolls don't completely double in size, they will continue to rise while baking.
Preheat oven to 350 degrees F.
Bake at 350 degrees for 15-25 minutes or until lightly brown.
While rolls are baking, prepare your frosting.
Remove from oven and either frost immediately if you would like frosting to melt into rolls, or wait until rolls have cooled, then frost.