1. Make batter: Whirl together eggs, flour, and milk in a blender until smooth.
2. Heat a small nonstick frying pan over medium heat and brush with butter. Pour in 2 tbsp. batter, swirling to spread evenly. Cook until golden underneath, 1 minute; flip over and cook 30 seconds. Make remaining crêpes, brushing pan with butter and stacking finished crêpes.
3. Make filling: Stir together ricotta, sugar, zest, and salt in a medium bowl. Spoon 1 tbsp. filling into center of a crêpe. Fold crêpe in half, pressing gently to spread filling evenly, then fold in half again to form a triangle. Continue with remaining crêpes.
4. Melt 1 tbsp. butter in a large nonstick frying pan over medium heat. In batches, carefully add filled crêpes; cook until golden brown, turning once, 5 minutes total. Transfer to a platter and keep warm.
5. Make topping: Melt butter in pan over high heat. Add peaches, sugars, cinnamon, and juice; cook, stirring occasionally, until sugars melt, 4 to 6 minutes. Remove from heat; carefully stir in cognac. Pour peaches over crêpes and sprinkle with almonds.
Make ahead: Make and fill crêpes through step 3, cover, and chill overnight.
Note: Nutritional analysis is per serving.