Sweet treats are to commemorate the sweetest moment in life. Create her sweetest moment in life and show your sincerity for this moment. Shower her with some sweet treats with a twist to surprise and elevate the sweetness of the moment. Add in the ring or handwritten love notes to propose to her. She will be touched to tears when she least expect this proposal to happen and your extra effort to prepare handmade desserts for her will definitely add some brownie points to the proposal. Good luck!