Cut strawberry rhubarb into 1-inch (or more) thick pieces and place into two wide break pans. Divide granulated brown sugar between the 2 pans (use a knife to get the sugar down between the rhubarb pieces).
For cake batter, cream white sugar and butter. Add egg and mix.
Alternate flour and baking powder. Add milk.
Divide batter and pour over rhubarb in the two pans. Bake for 45 minutes to 1 hour at 350° (test with a toothpick to see if done). Go around edge of pan with a knife and invert on a cookie sheet while still hot. Cut and serve with fresh cream poured over the top.