I have a white mulberry tree, and its fruit has presented some conundrum. They're not actually white, more a pastel purple - though that mean they don't exactly look like a normal rich blueberry or mulberry pie when baked. Still, I picked a bunch and stuck them in the freezer to try a pie later, and people liked it. Note: don't worry about the little stems, they bake soft. The pie turns out rather like fig newton filling, though, very crunchy with all the little seeds.
White Mulberry pie
1 Premade crust
4 cups mulberries
2/3 cup sugar
1/4 cup corn starch
Juice of 1/2 lemon
(Spices equal maybe 1/2-3/4 tsp added together)
Preheat oven to 350F
Mix everything but the crust - that goes in the pie tin. Once everything is a goopy thick mixture, use a spatula to get it scraped and splatted into the pie crust, and smoothed to pretty flat and level. Do whatever you like to the edges of your pie crust - some folks like to put a second crust on top and crimp, or lattices, or what have you. I just fold it over to create a rim, because it amuses me.
Bake for 45 minutes, let cool at least 10 minutes. Goes great with bluebell ice cream.