Preheat oven to 400 degrees Fahrenheit. Line a 12 regular-sized muffin tray with cupcake liners. In a large mixing bowl, beat the eggs and sugar with electric mixer until thickened and turned pale yellow in color, about 4-5 minutes. You can also use a handheld mixer or a whisk. Then add the oil, pure maple syrup and greek yogurt and mix until just combined.
In a smaller bowl, add the almond flour and plain flour, baking powder, salt, and whisk to combine. Divide the flour into 3 and add 1/3 at a time into the wet ingredients, mixing with a handheld whisk after each addition. Don't over-mix or you'll get dense muffins.
Zest and juice the lemon and whisk into the batter until combined. Lastly, fold in gently the blueberries using a spatula. If using frozen blueberries, don't thaw the berries and add them straight into the batter and gently fold it in.
Divide batter into muffin tins, filling liners to the top or until all of the batter is used up. Top with the flaked almonds. Bake for 20-22 minutes or until tops are golden and a toothpick inserted into the center comes out clean. Remove muffins from tin and cool completely on a wire rack.