Place flour, yeast, salt, and sugar in a mixing bowl and stir to combine. Add egg yolks and slowly drizzle in water while mixing. Knead until the mixture comes together as a sticky, smooth, and soft dough. Spray dough with cooking spray and cover bowl with plastic wrap. Let dough rise at room temperature for 2 hours.

Coat a large baking sheet with avocado oil. Divide dough into 15 parts, roll each piece into a ball, and place them on prepared baking sheet. Cover balls of dough with a slightly damp linen towel and let them rise for 30 minutes.

Pour avocado oil into a large, deep skillet until it is one-third to halfway full and warm it to 375°. Using your forefinger and thumb, make a hole in the center of each dough ball and gently slip them into the hot oil. Fry until lightly golden brown all over, turning as necessary. Drain on a paper bag. Top sfenj with powdered sugar or honey and enjoy immediately.