Preheat your oven to 375°F (190°C). Generously grease a 12-hole friand tin or a standard muffin tin with melted butter or cooking spray to prevent sticking.

Place the unsalted butter in a small saucepan over medium heat. Cook until it melts and begins to bubble, swirling occasionally, until it smells nutty and golden brown specks form at the bottom (about 5-7 minutes). Remove from heat and let it cool slightly.

In a large mixing bowl, whisk together the almond flour, powdered sugar, all-purpose flour, and a pinch of salt until well combined and completely lump-free.

Make a well in the center of the dry ingredients and pour in the lightly whisked egg whites, lemon zest, and vanilla extract. Gently stir until just combined, being careful not to overmix.

Gradually pour the warm browned butter into the batter, gently folding it in until the mixture becomes smooth, thick, and glossy.

Divide the batter evenly among the prepared tin holes, filling each about two-thirds full. Gently press 3 to 4 fresh blueberries into the top of each unbaked friand.

Bake in the preheated oven for 18 to 20 minutes, or until the edges are a deep golden brown and a skewer inserted into the center comes out clean.

Let the friands cool in the tin for 5 minutes before carefully transferring them to a wire rack. Dust with an extra pinch of powdered sugar before serving warm alongside a fresh cup of coffee or tea.