Preheat the oven to 350 F. or 180 C. Butter a 2 piece tarte pan and place a piece of parchment cut to fit in the bottom. Butter the parchment.
Combine almond flour, salt and baking powder in a bowl, set aside.
In the bowl of your mixer with a whisk attachment, add the eggs, sugar and vanilla. Beat on high until all the sugar is dissolved and mixture is light in color, about 5 minutes.
Meanwhile, using a small steel bowl that fits snuggly on top of a pot or a double boiler add enough water to the bottom pot and simmer lightly without touching the top bowl or pot. Add the chocolate and butter to the top bowl or pot. Over low heat, melt the butter and chocolate. Stir and remove from the heat.
Zest the lemon and mix into the dry ingredients. Juice the lemon and mix into the egg/sugar mixture.
Fold the egg/sugar mixture into the dry ingredients using a spatula. Give the chocolate mixture a stir before folding gently into the batter until no dry ingredients remain.
Pour the batter in the prepared tarte pan. Tap gently on the counter to remove air bubbles. Place in the pre-heated oven, lower third rack. Bake until golden and set about 35- 45 minutes. Check with a toothpick that it is no longer wet.
Cool completely in the pan before removing the tarte pan ring. If it sticks, use a bamboo skewer to go around the edge before removing.
Sprinkle with sifted, powdered sugar. Serve with cream and berries. Always naturally gluten free.