How to make a smooth transitioning hole in a cookie with glazing

Question

Problem

I modeled this cookie and only thing left is to put a hole in glazing. I tried doing it by modeling hole object (more images below) with smooth curve and applying boolean modifier but I get sharp edge at the top.

Question

How can I remove this sharp edge so that glazing looks smooth and flowy? Or how you would suggest making a hole in the glazing?

Things I'm considering

I guess what I want is to keep constant curvature between hole and glazing or at least tangent surface. I have few ideas how to do that:

1. Some kind of fillet tool to smooth sharp edge (idk if blender have something like that)
2. Somehow snap hole object vertices to the glazing (idk if possible) and model funnel shaped object from that
3. Manually adjust each vertex of hole object to closely follow surface curvature (not ideal because hard to adjust)

Any help, ideas or references are appreciated, Thanks

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Cookie hole I want to model:

Cookie I modeled without the hole

Hole object used for boolean modifier

Answer 1

Go tab into Edit Mode and add/position a cylinder to the spot you want to cut a hole in. Make sure it extends to the other side as well. Select the whole cylinder and press Ctrl+F > Intersect (Knife).

Then delete the entire cylinder. You are left with 2 holes on both sides. Select Edges Loops on both sides and press E to extrude but cancel operation with Esc. This will create duplicate vertices. Press S followed by Shift+Z to scale along the $XY$ plane and moving mouse inwards. Press Ctrl+E > Bridge Edge Loops.

Then again select the inner Edge Loops and press Ctrl+B to bevel edges. Move your mouse forward and increase geometry as needed by scrolling middle mouse button forward.

Add some Loop Cuts by hovering mouse between both opening ends and pressing Ctrl+R and scrolling middle mouse forward. You can also use Proportional Editing to scale the Face Loops and get a smoother transition by scaling with S and Shift+Z.