Preheat oven to 180 degrees Celsius. Grease 2 medium sized donut pans with olive oil and set aside.
Add the almond meal and coconut sugar to a large mixing bowl. Into the bowl sieve the buckwheat flour, tapioca starch and baking powder and whisk to combine.
Crack the eggs into a small bowl and whisk. Set aside.
Add the coconut oil to a small saucepan on a medium heat to melt. Once melted, add the plant-based milk and vanilla extract and whisk to combine. Remove from the heat.
Make a well in the dry ingredients and pour the milk mixture in.
Mix through slightly and then add the whisked egg and whisk through completely (this is so the hot liquid doesn't cook the egg).
Spoon the mixture into a well-oiled donut pan. Make sure the mixture doesn't go above the centre "hole" otherwise there will be no hole in the donut once cooked.
Bake for 12 minutes or until the donuts spring back when gently pushed down. Be careful not to overcook (mixture will go golden brown - if you let them cook until golden brown they will be too dry). Once removed from the oven, allow to cool in pan for about 5 minutes and then turn onto a cooling rack.
To make the glaze, sieve the icing sugar into a bowl. Add the milk and lemon juice and whisk to combine.
Dunk each donut face side down into the glaze and then place onto a plate or wire rack.
Store in an airtight container at room temperature for 2-3 days. These donuts are best eaten within the first 1-2 days.