Make the Jam: Place the strawberries, sugar and lemon juice in a 4-quart saucepan and cook over medium-high heat, stirring occasionally, until reduced to 4 cups, about 12 minutes. Allow to cool completely. (The jam can be stored, covered, in the refrigerator for up to 3 days.)
Preheat oven to 375 degrees F and adjust an oven rack to the lower third position, and place a baking sheet on the rack below.
Make the Biscuit Cobbler Topping: In a large bowl, whisk together the flour, sugar, baking powder and salt. Using a pastry blender, cut in the butter until the largest pieces are the size of peas. Using a fork, stir in the heavy cream until a dough starts to come together but is still crumbly. Turn the dough out onto a clean work surface and knead briefly to form a cohesive dough. Pat the dough into an 8-inch round and cut into 8 wedges.
Spread the jam onto the bottom of a 9½-inch deep-dish pie plate or skillet. Arrange the dough on top in a round. Brush the dough with heavy cream and sprinkle with sanding sugar. Bake until the strawberry jam is bubbling and the cobbler is golden brown, about 50 minutes. Allow to cool to warm room temperature before serving.