Make the pears. Core and peel the ripe fruit. Cut into small slices and put the slices into a bowl. Toss with a tablespoon of lemon juice.
In a nonstick sauté pan, melt the butter and spread it around the pan. Slide in the pears, one flat side down, in a single layer, and let them sauté for about two or three minutes on each side. Turn. If the sautéed side isn’t nicely golden brown, sauté on that side some more. When the pear slices are golden brown, they are ready to served. If the pancakes are not ready yet, hold in the sauté pan.
Make the pancakes. In a medium bowl, mix together the flour, baking powder, sugar and 1/8 tsp salt using a fork. Set aside.
Separate the eggs one at a time, putting the yolk into one small dish and the white into another. Check them for freshness, then put each yolk into a large bowl and each white into a medium bowl. If you have an unlined copper bowl, use that for the whites (see Kitchen Notes).
Add the ricotta to the yolks in the large bowl and mix them together, using a whisk. Beat for about 45 seconds, until they are all blended together and fluffy. Mix in the milk. Gradually stir in the flour mixture, working lightly, and then 1 tablespoon of lemon zest. Set the bowl of batter aside.
Add a pinch of salt to the egg whites. Then, using an electric hand mixer, beat the egg whites until they form stiff peaks.
Drop about 20 percent of the beaten egg whites atop the batter and gently stir. Then, working in small batches, fold the rest of the egg whites into the batter. When everything is incorporated together evenly, start heating the sauté pan over a medium flame, add in a bit of oil, and get your plates ready. Also place a heatproof plate in a warm oven, to hold the cooked pancakes.
When the pan appears hot enough, cook one sample pancake to see if the pan is ready. If that pancake looks all right, then proceed. Cook the pancakes in batches of three or four. Hold the cooked ones on the prewarmed plate in the oven, under a foil tent.
When everything is ready, plate them, top with a heap of the sautéed pears and a scattering of the remaining lemon zest, and serve.