Special equipment: a ring mold that fits the mouth of your serving glass
For the peaches: Add the blueberries, 2 tablespoons brown sugar and 1 cup water to a medium saucepan and bring to medium heat. Simmer until syrupy, about 10 minutes. Remove from the heat.
Meanwhile, punch out circles from the pound cake using a ring mold and reserve.
Put the peaches, 1/2 cup brown sugar and 2 tablespoons water in a small saucepan and cook, covered, over medium heat until the peaches are soft and tender, 5 to 10 minutes.
For the maple pecans: Preheat the oven to 350 degrees F.
Mix the pecans, maple syrup, olive oil and salt in a bowl. Spread on the prepared baking sheet and bake for 15 minutes. Break apart into pieces.
For the vanilla whipped cream: Add the cream to the bowl of a stand mixer fitted with the whisk attachment. Whip to soft peaks. Add the granulated sugar and vanilla and whip to stiff peaks.
To assemble: In a wide-mouth serving glass or parfait dish that fits the circles of pound cake, layer a pound cake circle, a layer of blueberries, another pound cake circle, a layer of peaches, a large dollop of whipped cream and a sprinkle of nuts. Repeat with the remaining ingredients in 5 more glasses.