Preheat the BBQ. Drizzle the plums with extra virgin olive oil and place them on the hot plates. Cook for a few minutes, turning occasionally until lightly charred.
Transfer the cooked plums to a large bowl, drizzle with honey, and gently stir to combine.
In a food processor, combine the ricotta, lemon juice, lemon zest, vanilla extract, and a pinch of salt. Blitz until smooth and whipped.
Spread the whipped ricotta on a serving plate. Top with the honeyed plums and scatter with thyme leaves. Sprinkle with crushed pistachios before serving.