Preheat oven to 425 degrees.
Cut the passion fruits in half and scrape pulp and seeds into a microwave safe bowl.
Microwave passion fruit pulp for 30 seconds to 1 minute, until very hot.
Strain pulp through a fine mesh sieve, stirring and pressing on pulp and seeds to extract all the liquid pulp. Discard seeds. Reserve 5 tablespoons of the passion fruit juice for the glaze.
In a standing mixer, cream butter and sugar until light and fluffy.
Whisk together the eggs, 3/4 cup passion fruit pulp, lime juice, vanilla, and yogurt.
Whisk together flour, baking powder, and salt.
Add the liquid ingredients to the butter/sugar mix, alternating with the dry ingredients. Finish with the dry ingredients, folding them in by hand. Fold in the pineapple (drained and finely chopped). Do not over mix.
Line muffin tins with paper. Fill 18 regular muffin tins (or 10 jumbo) three-quarters of the way full.
Place chopped Brazil nuts, oats, and brown sugar in a bowl. Add 3 tablespoons butter. Mix butter into the oats and nuts with your fingers, until well mixed and crumbly.
Sprinkle about 1 tablespoon of oat/nut mixture over the top of each muffin.
Bake the muffins on the center rack at 425 degrees for 5 minutes. Lower the heat to 375-400 degrees, and bake for 10 minutes more.
Check for doneness. Muffins should spring back slightly when touched. Larger muffins may require an extra 5 to 8 minutes.
Remove muffins and let cool in the pan on a rack for 5 minutes. Remove muffins from pan.
Whisk 4-5 tablespoons passion fruit juice, melted butter, and 1 tablespoon lime juice into the powdered sugar. Add a pinch of salt and 1/2 teaspoon vanilla. Thin with more juice or water if necessary, or add more powdered sugar if the glaze is too runny (glaze will firm up slightly as it cools).
Drizzle glaze over top of muffins. If glaze thickens, try reheating for a few seconds in the microwave.