Combine flour, sugar, and salt in a bowl. Grate the butter into the flour. Coat in flour and grate directly into bowl, trying to touch as little as possible so that it doesn't melt from the heat of your fingers. Recoat butter with flour mixture as needed. Once grated, use the tips of your fingers to work the butter into the flour until it is a coarse crumble.

Add water. Use a butter knife to "cut" the water into the pastry: cut through the forming clumps into still powder-y areas. Add more water a couple tsp at a time if not combining.

Once most of the flour is moistened, use your hands to form the dough into a ball and pat in any extra flour.

Cover with plastic wrap and chill in fridge for at least 2 hours.

Alternative method: add flour, sugar, salt, and grated butter into the bowl of a food processor. Process until coarse crumbles. Add water and process until dough starts to adhere to itself. Personally I find this creates a lot more dishes to wash and you have a higher risk of over processing the dough (which forms gluten bonds and tough dough).

Combine in a bowl and allow to sit and blend in the fridge for at least 1 hour.

Combine all ingredients in a bowl. Using two butter knives, chop across the bowl to combine. Once mostly blended, you can use your fingers to get it the rest of the way there. Set aside in the fridge until needed. Like the pastry, this can also be blended in a food processor (see above re: dishes).

Have a clean, dry 1/2 c muffin tin ready.

Roll out dough on a heavily floured surface to 1/8-1/4" thick. Use a 5" biscuit cutter to cut 12 rounds. This can be done in batches if your work surface isn't large enough.

Make sure one side of your dough is very floured. This will make it easier to extract the crisps after baking. Place floured side down over the center of each muffin well and gently press the dough into the well. Repeat with the rest of the dough.

Chill for 10-15 minutes in the fridge. Just rolling out the dough starts warming it up and you want it to be nice and cold for the flaky texture. Use this time to start preheating the over to 350F. Once slightly chilled again, remove from fridge and puncture the bottom of the crisp shells 3-4 times with a fork. This prevents really big air pockets from forming in the shell and spilling the filling out.

Add ~2 tbsp of fruit filling to each shell. Leave just enough space to put the crisp topping on without heaping too much over the top of the pan.

Carefully sprinkle on 1 tbsp of topping to each crisp. Try not to go outside the edge of each shell so that it is easier to remove later.

Back for about 40 minutes. Crisp will be golden brown and you can see the fruit filling bubbling underneath.

Remove from oven and immediately run a small, sharp knife around the edge of each crisp to cut through any filling that has bubbled over. Allow to cool for at least 15 minutes before removing from pan.