Step 1 Peel and grate sweet potatoes. Take butter and oil in a non stick or heavy bottomed steel pan. Heat it on medium and add grated sweet potato. Fry sweet potato stirring for a minute or so. Add milk and bring it to boil. Put the heat to medium and let it simmer. Stir occasionally. Add rose petals and cardamom powder.
When milk starts to thicken add sugar and cook further. Remove from heat after 20 minutes or when it reaches the perfect consistency. It will thicken more when it cools down.
Add rose syrup to the kheer when its completely cooled. Refrigerate, for 2 hours before serving. Garnish with some rose petals.