My TikZ portrait:

\documentclass[tikz]{standalone}

% colors
\definecolor{simpson}{HTML}{FFD912}
\definecolor{hair}   {HTML}{976530}
\definecolor{tshirt} {HTML}{505050}
\pgfdeclareverticalshading {sideburn}{2cm}
{%
  color(0cm)=(gray!20);
  color(0.7cm)=(hair);
  color(2cm)=(hair)
}

\begin{document}
\begin{tikzpicture}[line cap=round,line join=round,very thick]
% background
\fill[bottom color=cyan,top color=white] (0,1.2) circle (3.5);
% head
\draw[fill=simpson]                 (1.68, 1.9) arc (0:180:1.75)
   to[out=270,in=130]              (-1.3 , 0.7) to[out=310,in=70,looseness=0.9] (-0.8,-1.2)
   to[out=330,in=210]               (0.8 ,-1.3) to[out=110,in=250]               (1.1,-0.35)
   to[out= 30,in=180,looseness=1.5] (1.5 , 0)   to[out=0  ,in=300]               (2.2, 0.4)
   to[out=120,in=270,looseness=0.7] (1.7 , 1)   to[out=90,in=270] cycle;
% mouth
\draw (0.1,0.1) to[out=340,in=0,looseness=0.65]  (1.5,0);
\draw (0,-0.1)  to[out=90 ,in=60] (0.1,0.1) to[out=60,in=220] (0.2,0.2);
% glasses
\begin{scope}[line width=0.8mm]
  \draw (-1.2,1.5) --++ (1,0);
  \draw (0.7,1.7) to[out=10,in=170] (1.15,1.7);
  \draw[fill=white,line width=0.7mm,rounded corners] (-0.4 ,1.1) rectangle (0.7,1.8);
  \draw[fill=white,line width=0.7mm,rounded corners]  (1.15,1.2) rectangle (2.1,1.9);
  \fill (1.73,1.55) circle (0.8mm);
  \fill (0.1,1.45)  circle (0.8mm);
\end{scope}
% nose
\draw[fill=simpson] (1.05,1.5) to[out=300,in=90] (1.75,1) to[out=270,in=330] (1.2,0.8);
% goatee
\draw[fill=hair] (0.5,-0.6) to[out=270,in=160] (1,-1.1) to[out=70,in=330] (0.9,-0.5) -- cycle;
% hair
\draw[shading=sideburn]
 (-1.15,0.6) + (30:0.35)
   to[out=300,in=180] (-0.5,0.45) to[out=0,in=270] (-0.2,0.65)
   to[out=90,in=330,looseness=0.5] (-1,1.5) to[out=150,in=240,looseness=0.8] (-0.75,3.15)
   to[out=330,in=200]  (0.8 ,3)   to[out=160,in=320] (-0.1,3.4) to[out=0,in=150] (2.1,2.7)
   to[out=40,in=270]   (2.2 ,2.9) to[out=90,in=330]   (1.4,3.8) --++ (0.6,-0.1)
   to[out=150,in=40]  (-0.9 ,3.8) to[out=180,in=80]  (-2.3,2.8) to[out=30,in=190] (-2,2.9)
   to[out=260,in=130] (-1.55,0.9) to[out=320,in=90]  (-1.5,0.6) arc (180:30:0.35) -- cycle;
% ear
\fill[simpson] (-1.15,0.6) + (330:0.35) arc (330: 90:0.35);
\draw          (-1.15,0.6) + (330:0.35) arc (330: 30:0.35);
\draw          (-1.15,0.5) +  (35:0.25) arc  (30:145:0.25);
\draw          (-0.9 ,0.7) + (230:0.3)  arc (230:170:0.3);
% t-shirt
\draw[fill=tshirt]    (-0.9,-1.1) to[out=330,in=210] (0.9,-1.2) to[out=30,in=30] (0.9,-1.4)
   to[out=210,in=330] (-0.9,-1.3) to[out=150,in=150] cycle;
\draw[fill=tshirt]    (-0.9,-1.3) to[out=230,in=60] (-1.6,-1.9) arc (243:297:3.5)
  to [out=130,in=300]  (0.9,-1.4) to[out=200,in=340] cycle;
% circle
\draw[line width=2mm] (0,1.2) circle (3.5);
\end{tikzpicture}
\end{document}