Ricotta-filled crepes become bright and tangy when crowned with tangerine and lemon marmalade, best made in winter, when citrus is at its peak. Honeybell or blood oranges and red grapefruit also work well in a marmalade.
Whisk together flour, sugar, and salt. Whisk together milk, vanilla, and eggs. Gradually add milk mixture to flour mixture, whisking until smooth. Whisk in melted butter. Strain through a fine sieve; discard lumps. Refrigerate batter for at least 2 hours or overnight.
Preheat oven to 200 degrees. Combine ricotta and zest. Lightly coat a 6-inch crepe pan or nonstick skillet with butter. Heat over medium heat until just starting to smoke. Remove from heat; pour 2 tablespoons batter into center. Swirl to cover bottom. Reduce heat to medium-low; return pan to heat. Cook until edges are golden and center is dry, about 45 seconds. Flip; cook for 45 seconds.
Slide crepe onto an ovenproof plate; cover with foil, and transfer to oven. Repeat with remaining batter, coating pan with butter as needed.
Fill each crepe with 2 to 3 tablespoons ricotta mixture. Fold into quarters to form a triangle. Make stacks of 3 crepes. Top with marmalade.