Whisk 5 cups flour, 1 tablespoon brown sugar, baking powder, and salt in a large bowl. Cut lard into flour mixture until mixture resembles coarse crumbs. Whisk cold water, 1 egg, and vinegar together in a separate bowl. Make a well in the center of flour-lard mixture. Pour egg mixture into well and mix until dough forms.
Divide dough into fourths; wrap 3/4 of the dough in plastic wrap. Form the remaining 1/4 of the dough into 12 balls and flatten each ball into a disc. Press each disc into the bottom and up the sides of a muffin cup.
Beat cream cheese and white sugar together in a bowl until smooth. Add 1/3 cup melted margarine, milk, 2 eggs, and vanilla extract to cream cheese mixture; beat until smooth. Pour cream cheese mixture into prepared muffin cups.
Mix 1/2 cup flour, 1/2 cup brown sugar, and 1/4 cup melted margarine together in a bowl with a fork until crumbly, adding more flour and brown sugar as necessary until crumb topping has desired consistency. Sprinkle topping over each muffin cup.
Bake in preheated oven until filling is set, 12 to 15 minutes.