In a small bowl, combine water, sugar, and yeast. Let sit for about 10 minutes, until bubbled and foamy. In the bowl of a stand mixer with dough hook, add yeast mixture, milk, butter, and salt. Stir to combine.
With stand mixer on low, slowly add about 3-1/2 cups flour until a sticky ball of dough forms. Turn dough out onto a well floured surface and knead until a smooth, elastic dough forms, adding flour as needed.
Place dough in a large bowl sprayed with cooking spray and cover with a dry cloth. Let sit for about an hour, or until doubled in size.
Line a baking sheet with parchment paper. Punch down dough, and divide into about 10 pieces. Roll each piece into a ball, pulling down outer edges and pinching together at the bottom of the ball. Place ball of dough on baking sheet with pinched side down. Repeat with remaining dough. Cover and let rise for at least 30 minutes.
Preheat oven to 425 degrees F. Prepare the dutch crunch topping. Combine yeast, warm water, and sugar in a medium bowl and let proof for about 10 minutes. Add oil, salt, and rice flour and whisk well to combine. Let sit for another 10 minutes.
Spoon rice flour mixture onto rolls. Cover each roll well, using all of the rice flour mixture. Bake rolls for about 15-18 minutes, until golden brown.