A slump is in the family of cooked or stewed fruit with raised dough on top. Some are golden brown baked pastry over seasonal fruits like cobblers and some are simmered on the stove like a slump or a grunt (which is the Cape Cod name for slump). So this is more like a big boiled dumpling over cooked fruit, which slumps when you put it on the plate. It reminds me of my mom's favorite lunch of tomato soup with big doughy dumplings. She'd slip the batter off a large spoon into the slow simmering red bath of tomato soup and they'd immediately sink. It was a bit of a treasure hunt to find the dumplings at the bottom of her Revereware saucepan. My love of rhubarb in anything comes from my time in England and time in my garden where 2 large rhubarb plants are its focal point.
In a saucepan with a tight-fitting lid, combine the strawberries, rhubarb, sugar and 1/2 cup water. Cook over medium heat at a simmer for about 10 minutes.
Meanwhile, in a bowl, stir together the flour, baking powder and salt. Add the milk and quickly combine. Drop the batter by spoonfuls onto the surface of the slightly simmering fruit. Cook for 10 minutes uncovered, then place a lid on and cook another 10 minutes.
Serve in shallow bowls, topped with whipped cream.