Preheat oven to 350°F. Line an 9-inch cake pan with parchment paper. You can slightly grease the pan with butter or cooking spray so parchment paper stays better in place.
Peel, quarter, core and slice the pears thinly. Chop the dark chocolate bar with a knife into small pieces.
In the first large bowl, sift flour, baking powder and salt.
In the second large bowl, add ¾ cup sugar and 3 eggs. Using electric mixer, beat eggs and sugar for about 1-2 minutes or until the mixture becomes thick and one consistency.
Add ⅔ cup Greek plain yogurt, ¼ cup milk, ¼ cup olive oil and 1 teaspoon pure vanilla extract to the bowl. Beat it again with the mixer for about 30 seconds or until all well combined.
Turn the mixer on the lower speed and slowly add there the dry ingredients. Once the batter is formed, turn off the mixer.
With as silicone spatula, fold in half of the sliced pears and all the chocolate chunks.
Pour the cake batter into prepared pan. Place the remaining pear slices on top, arranging them in circles. Sprinkle with sliced almonds on top.
Bake the cake for about 40-50 minutes or until the toothpick comes out clean and the cake is golden brown on top. Let it cool down slightly before removing from the pan. Right before serving, dust it with powdered sugar.