1. In a wide saucepan, combine the blackberries, lemon juice, sugar and thyme. Cook over low heat until the sugar melts, then bring to a boil over high heat. Boil for 10 to 15 minutes, stirring frequently, until blackberries become thick and syrupy.
2. Stir in the vinegar and simmer for an additional minute. Transfer to a storage jar and set aside to cool to room temperature. Refrigerate for at least 2 hours. Compote will continue to set and thicken as it cools.
3. Preheat oven to 375°F. Slice baguette on the diagonal into 1/4-inch slices. Lightly brush both sides with olive oil and arrange on a baking sheet. Bake until lightly toasted and golden, about 10 to12 minutes.
4. Roughly chop the blue cheese into large chunks. In the bowl of a stand mixer with the whisk attachment, combine the blue cheese and ricotta. Whisk together the cheeses until light and creamy, starting on low speed and gradually increasing to medium-high, about 2 minutes.
5. To assemble, spread about a tablespoon of the whipped blue cheese and ricotta on a slice of toasted baguette. Spoon a couple teaspoons of blackberry thyme compote on top. Drizzle with honey, sprinkle with flaky sea salt, and garnish with a few fresh thyme leaves. Serve immediately.