The BEST mixed berry cobbler you'll ever have! Fluffy oat biscuits paired with a double-whammy of juicy berries make for one killer cobbler.---Eat it warm with lots of whipped cream!
Make the filling: In a large saucepan over medium-high heat, bring berries, sugar, and lemon juice to a low simmer. Remove 1/2 cup liquid and whisk with cornstarch until smooth. Add cornstarch mixture to saucepan and stir berries occasionally until bubbly and thickened. Remove from heat and pour in the bottom of a 9x13 baking pan. Set aside.
Make the biscuits: In a large bowl, combine flour, oats, baking powder, baking soda, salt, and sugar. Cut in butter with a pastry cutter until crumbly. Pour milk over mixture and stir until a dough forms.
Drop dough by the spoonful over berry filling. Brush biscuits with heavy cream. Bake cobbler at 350F 20-25 minutes or until biscuits are golden and filling is bubbly. Let cool 10 minutes then serve warm. Enjoy!