Step 1: Heat the oven to 425°F. Arrange the figs cut-side up in a shallow 2-quart baking dish.
Step 2: In a small bowl, whisk together the sugar, orange zest, red pepper flakes, lemon juice, orange juice, and miso until the miso is fully incorporated.
Step 3: Pour the miso-orange mixture over the figs and gently turn them to coat. Return the figs to a single layer with their cut sides facing up.
Step 4: Roast for 20 to 25 minutes, spooning the pan juices over the figs once or twice, until the fruit is soft and jammy and the juices have reduced to a glossy syrup.
Step 5: Squeeze a little additional lemon juice over the figs. Let them cool for at least 10 minutes; the syrup will continue to thicken as it stands.
Step 1: Divide the vanilla ice cream among 4 serving bowls. Spoon the warm or room-temperature figs and their syrup over the ice cream.
Step 2: Finish with the chopped pistachios and serve immediately.
