Preheat oven to 375 degrees F. Lightly grease a 10 or 12-inch skillet or 3-quart baking dish.

In a medium bowl, toss strawberries and rhubarb with sugar, orange juice, vanilla extract, and cornstarch.

Transfer fruit mixture to skillet or baking dish.

To make the biscuits, add flour, baking powder, baking soda, sugar, and salt to a food processor (or large bowl) and pulse until combined (or whisk by hand in bowl). Add butter and pulse until crumbly (or use a pastry cutter or forks). It should resemble coarse meal. If using a food processor, transfer flour mixture to large bowl, then stir in pistachios. Whisk together buttermilk and egg and add to flour mixture. Mix together with a spoon until just combined, creating a slightly tacky, very crumbly dough. Try not to over mix.

Flour your hands (you may have to flour hands a couple times) and gently form dough into 6-7 round, slightly flat biscuits. Place biscuits on top of the strawberry rhubarb mixture. Lightly brush the biscuits with buttermilk and sprinkle with coarse sugar.

Bake cobbler for 40-45 minutes until fruit is tender and bubbly and biscuits are cooked through and golden brown. If the biscuits are browning too quickly, lay a piece of tinfoil over the cobbler for the last 10 minutes.

Serve cobbler warm with a big scoop of vanilla ice cream or whipped cream!