Preheat your oven to 350F.
Butter a 9x13 baking dish and set aside.
Peel and core your apples. Cut into quarters and then slice thinly (1/8 inch). Add them to a large bowl.
Next, cut the pear from the core, in quarters, leaving the skin on. Slice into a variety of 1/8 inch slices or, into ½ inch cubes (if you want a different texture). Add to the bowl of apples.
Sprinkle the apples & pears with ¼ teaspoon of salt, vanilla, and cornstarch. Gently mix and set aside.
In another large mixing bowl, add the flour, sugar, & cinnamon and mix quickly with a fork. Add the stick of butter, then - using your hands - incorporate the butter into the dry mix. You’re going to ‘squish’ the butter in, using the heat from your hands to melt it slightly. Mix until the butter starts to clump with the flour, and then begin to crumble up the clumps, while also stirring it around. You want the end result to look like a mix of sandy dough with a few larger chunks.
Once the dough is ready, take the apples & pears and tip them into the prepared baking dish. Spread the fruit out evenly. Evenly spread the “sandy” butter & flour mixture over the fruit, in one layer.
Place on the middle rack of the oven and bake 40-50 minutes, or, until golden and slightly bubbly.
Let cool for at least 15 minutes before serving. I like mine to rest for about 40 minutes, so the cobbler is still warm, but not too warm to totally melt the vanilla ice cream I use for topping.